Interior Immigration Enforcement: 
Programs Targeting Criminal Aliens 
Marc R. Rosenblum 
Specialist in Immigration Policy 
William A. Kandel 
Analyst in Immigration Policy 
December 20, 2012 
Congressional Research Service 
7-5700 
www.crs.gov 
R42057 
CRS Report for Congress
Pr
  epared for Members and Committees of Congress        
Interior Immigration Enforcement: Programs Targeting Criminal Aliens 
 
Summary 
Congress has a long-standing interest in seeing that immigration enforcement agencies identify 
and deport criminal aliens. The expeditious removal of such aliens has been a statutory priority 
since 1986, and the Department of Homeland Security (DHS) and its predecessor agency have 
operated programs targeting criminal aliens for removal since 1988. These programs have grown 
substantially since FY2005.  
Despite the interest in criminal aliens, inconsistencies in data quality, data collection, and 
definitions make it impossible to precisely enumerate the criminal alien population, defined in 
this report as all noncitizens ever convicted of a crime. CRS estimates the number of noncitizens 
incarcerated in federal and state prisons and local jails—a subset of all criminal aliens—at 
173,000 in 2009 (the most recent year for which complete data are available), with state prisons 
and local jails each accounting for somewhat more incarcerations than federal prisons. The 
overall proportion of noncitizens in federal and state prisons and local jails corresponds closely to 
the proportion of noncitizens in the total U.S. population. 
DHS operates four programs designed in whole or in part to target criminal aliens: the Criminal 
Alien Program (CAP), Secure Communities, the §287(g) program, and the National Fugitive 
Operations Program (NFOP). The CAP, Secure Communities, and certain §287(g) programs are 
jail enforcement programs that screen individuals for immigration-related violations as they are 
being booked into jail and while they are incarcerated; the NFOP and some §287(g) programs are 
task force programs that target at-large criminal aliens. This report describes how these programs 
work and identifies their common features and key differences among them.  
While consensus exists on the overarching goal to identify and remove serious criminal aliens, 
these programs have generated controversy, particularly Secure Communities and the §287(g) 
program. On one hand, the Obama Administration and other supporters of jail enforcement 
programs see them as efficient and even-handed ways to identify criminal aliens. The 
Administration has taken steps to strengthen and expand Secure Communities and plans to 
implement the program in every law enforcement jurisdiction in the country by the end of 2013. 
On the other hand, some lawmakers and advocacy groups have raised concerns that Secure 
Communities and the §287(g) program have not been narrowly targeted at serious criminal 
offenders and that the programs may have adverse impacts on police-community relations, may 
result in racial profiling, and may result in the detention of people who have not been convicted 
of criminal offenses and/or may not be subject to removal.  
Disagreements about the merits of jail enforcement programs overlap with a separate set of 
questions about the role of states and localities in immigration enforcement. These jurisdictional 
questions have focused in particular on Secure Communities, in part because the Obama 
Administration initially appeared to present it as a discretionary program but now takes the 
position that states and localities may not “opt out” of Secure Communities. 
Legislative issues related to Secure Communities and other ICE programs that Congress may 
consider include clarifying the role of state and local law enforcement agencies in immigration 
enforcement, the Obama Administration’s exercise of prosecutorial discretion, mandating new 
data collection in response to concerns over racial profiling at the state and local levels, and 
clarifying the statutory authority for states and localities to detain unauthorized aliens.  
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Interior Immigration Enforcement: Programs Targeting Criminal Aliens 
 
Contents 
Introduction ...................................................................................................................................... 1 
Defining “Criminal Aliens” ............................................................................................................. 2 
Quantifying the Criminal Alien Population ..................................................................................... 4 
Federal-Level Arrest Data ......................................................................................................... 4 
Federal, State, and Local Incarceration Data ............................................................................. 6 
Estimates from the American Community Survey .................................................................... 8 
Other Estimates of the Criminal Alien Population .................................................................... 9 
History of Criminal Alien Removal Programs............................................................................... 11 
ICE Programs Targeting Criminal Aliens ...................................................................................... 13 
Jail Enforcement Programs ...................................................................................................... 14 
Criminal Alien Program (CAP) ......................................................................................... 14 
Secure Communities ......................................................................................................... 15 
§287(g) Jail Screening Program ........................................................................................ 16 
Task Force Programs ............................................................................................................... 16 
§287(g) Task Force Program ............................................................................................. 16 
National Fugitive Operations Program.............................................................................. 17 
Differences Among Criminal Alien Enforcement Programs ................................................... 17 
DHS Enforcement Priorities and Discretion .................................................................................. 19 
March 2011 ICE Guidance Memo ........................................................................................... 20 
June 2011 ICE Guidance Memo .............................................................................................. 20 
August 2011 DHS Announcement and Review of Backlogged Cases .................................... 21 
Deferred Action for Childhood Arrivals (DACA) ................................................................... 22 
Appropriations ............................................................................................................................... 23 
Enforcement Statistics ................................................................................................................... 25 
Controversies Surrounding Interior Enforcement Programs ......................................................... 27 
The Rationale Behind Secure Communities and the §287(g) Program ................................... 28 
Concerns About Secure Communities and Other ICE Programs ............................................ 31 
Can Jurisdictions “Opt Out” of Secure Communities?............................................................ 37 
ICE Has Taken Steps to Address Concerns About Secure Communities and the 
§287(g) Program................................................................................................................... 38 
Legislative Issues ........................................................................................................................... 40 
The Role of State and Local Law Enforcement Agencies in Immigration Enforcement ........ 40 
Prosecutorial Discretion .......................................................................................................... 41 
Data on Racial Profiling .......................................................................................................... 42 
Immigration Detainers ............................................................................................................. 42 
Conclusion ..................................................................................................................................... 42 
 
Figures 
Figure 1. Criminal and Unauthorized Aliens ................................................................................... 3 
Figure 2. Federal Arrests by Citizenship Status and Type of Offense, 2001-2010 .......................... 5 
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Figure 3. Proportion of the U.S. and Incarcerated Population by Nativity and Citizenship, 
2001-2009 ................................................................................................................................... 11 
Figure 4. ICE Enforcement and Removal Programs in the Criminal Justice Process ................... 13 
 
Tables 
Table 1. Persons Arrested for Federal Offenses, by Legal Status, 2001, 2005, and 2010 ................ 4 
Table 2. Total and Noncitizen Incarcerated Population, Federal and State Prisons and 
Local Jails, 2001-2010 .................................................................................................................. 7 
Table 3. Offense Category of Sentenced Offenders, by Citizenship, 2001-2010 ............................ 8 
Table 4. ICE’s Primary Criminal Alien Enforcement Programs .................................................... 18 
Table 5. Appropriations for Programs Targeting Criminal Aliens, FY2004-FY2011 .................... 24 
Table 6. Primary Interior Enforcement Actions, by Program, FY2004-FY2011 ........................... 25 
Table 7. Ratio of Appropriations to Enforcement Actions, by Program, FY2004-FY2011 ........... 27 
Table 8. Removals and Returns Under Secure Communities and Arrests through the 
§287(g) Program, by Type of Offense, FY2006-FY2012 ........................................................... 32 
 
Appendixes 
Appendix A. Glossary of Terms ..................................................................................................... 44 
Appendix B. Data on Arrests and Incarceration of the Criminal Alien Population ....................... 45 
 
Contacts 
Author Contact Information........................................................................................................... 48 
 
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Interior Immigration Enforcement: Programs Targeting Criminal Aliens 
 
 
Introduction 
Congress has a long-standing interest in the criminal alien population and has supported efforts 
since the late 1980s to identify, detain, and remove these individuals. The Department of 
Homeland Security’s (DHS) Immigration and Customs Enforcement (ICE) agency operates four 
key programs to address this population. The Criminal Alien Program (CAP) is a screening 
program that identifies, detains, and initiates removal proceedings against criminal aliens, 
including within federal, state, and local prisons and jails. Secure Communities is an information 
sharing program between the Departments of Justice and Homeland Security that screens for 
removable aliens as people are being booked into jails. Agreements entered into pursuant to 
Immigration and Nationality Act (INA) §287(g) (“§287(g) agreements”) allow DHS to delegate 
certain immigration enforcement functions to specially trained state and local law enforcement 
officers, under federal supervision. The National Fugitive Operations Program (NFOP) pursues 
known at-large criminal aliens and fugitive aliens. 
Funding for programs targeting criminal aliens has expanded considerably since FY2005, as has 
the number of aliens arrested through them. Congress appropriated a total of about $608 million 
to ICE for these four programs in FY2012, up from $23 million in FY2004. At the same time, the 
number of aliens arrested through programs targeting criminal aliens increased from about 11,000 
to over 293,000 in FY2011 (the latest year for which data are available). 
While Congress has targeted funding for the removal of criminal aliens, the majority of 
unauthorized aliens in the United States have not been convicted of a crime. Some have criticized 
programs designed to remove criminal aliens because these programs have also identified 
removable aliens who have no criminal record or have committed only nonviolent crimes. Others 
note, however, that all removable aliens have violated U.S. law. 
Partly for these reasons, the continued growth of programs targeting criminal aliens raises a 
number of potential issues for Congress, including questions about whether and how DHS should 
exercise prosecutorial discretion in executing such programs, the role of state and local law 
enforcement agencies in immigration enforcement and whether they can “opt out” of certain 
federal enforcement programs, whether Congress should take steps to guard against racial 
profiling and other adverse consequences that may be associated with programs targeting criminal 
aliens, and possible legislation governing DHS’s use of immigration detainers to request that state 
and local law enforcement agencies hold immigrants until they can be placed in removal 
proceedings. 
This report begins by defining and quantifying the criminal alien population, to the extent 
possible. The following sections describe current and historical programs designed in whole or in 
part to target this population, including CAP, Secure Communities, the §287(g) program, and 
NFOP. After describing how these programs function and key differences among them, the report 
reviews their recent appropriations history and enforcement statistics. 
The final sections of the report describe the controversies surrounding certain programs targeting 
criminal aliens—particularly the Secure Communities program and the §287(g) program—and 
legislative issues that may arise as a result. On one hand, these programs are seen as highly 
efficient and even-handed ways to identify criminal aliens who may be removable, and DHS has 
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taken steps to strengthen and expand Secure Communities and other enforcement programs based 
within jails and prisons. On the other hand, critics of Secure Communities and related programs 
have argued that the programs are not sufficiently focused on serious criminal aliens, and that 
they may damage police-community relations, may result in racial profiling, and may result in the 
wrongful incarceration of people who have not been convicted of criminal offenses. These 
concerns have contributed to a separate set of questions about whether or not states and localities 
may refuse to participate or limit their participation in DHS’s jail enforcement efforts.  
Defining “Criminal Aliens” 
For over a century, U.S. immigration law has identified certain crimes that make an alien 
ineligible for admission to the United States and/or subject to deportation.1 Such crimes include 
crimes of “moral turpitude,” crimes involving controlled substances, certain firearm offenses, and 
crimes related to espionage, sabotage, and related offenses.2 Yet the term “criminal alien” is not 
specifically defined in immigration law or regulation, and people use it to refer to several 
different types of noncitizen offenders.3 At the broadest level, a “criminal alien” is any 
noncitizen who has ever been convicted of a crime in the United States. This report adopts this 
broad definition unless otherwise noted. See Appendix A for a glossary of additional terms 
related to the criminal alien population. 
Not all criminal aliens are unauthorized or removable, and some removable aliens are not 
criminals (see Figure 1).4 Three groups of criminal aliens can be distinguished. First, the set of 
all criminal aliens includes both unauthorized aliens,5 all of whom are potentially removable, and 
legal aliens,6 who may or may not be removable depending on specific crimes committed. 
Second, a subset of criminal aliens convicted of removable criminal offenses are subject to 
                                                 
1 The Immigration Act of 1917 (P.L. 64-301) and subsequent legislation made certain inadmissible aliens subject to 
“exclusion” and certain aliens within the United States subject to “deportation.” Pursuant to §§301-309 of the Illegal 
Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA, P.L. 104-208, Div. C), deportation and 
exclusion proceedings were combined into a unified “removal” proceeding. This report uses “deportation” to refer to 
such enforcement prior to the 1997 implementation of IIRIRA and “removal” to refer to such enforcement since 1997. 
2 Whether a crime involves moral turpitude has been determined by judicial and administrative case law rather than a 
statutory definition. In general, if a crime manifests an element of baseness or depravity under current mores it involves 
moral turpitude. See CRS Report RL32480, Immigration Consequences of Criminal Activity, by Michael John Garcia. 
3 Noncitizens include permanent immigrants (i.e., aliens admitted as legal permanent residents (LPRs), or “green card” 
holders), legal nonimmigrants (i.e., aliens admitted on temporary visas), and unauthorized aliens (i.e., aliens who enter 
without an inspection or overstay a temporary visa). 
4 Estimates of the unauthorized resident alien population in the United States range from 10.8 to 11.5 million in 2011; 
see CRS Report RL33874, Unauthorized Aliens Residing in the United States: Estimates Since 1986, by Ruth Ellen 
Wasem. By comparison, the CRS estimate of the criminal alien population in jails and prisons computed in this report 
was 173,000 in 2009 (the latest year for which complete data are available); see “Quantifying the Criminal Alien 
Population” in this report. Nationally, incarcerated persons represent roughly one-third of the total correctional 
population, with persons on probation and parole comprising the other two-thirds; see footnote 39. Assuming the same 
ratio applies to foreign-born criminals, the estimated total foreign-born correctional population would be 519,000. This 
estimate includes legal and unauthorized immigrants, and does not include aliens previously convicted of crimes who 
have already completed their criminal sentences. Also see “Other Estimates of the Criminal Alien Population” in his 
report. 
5 Unauthorized aliens are foreign nationals who have entered the United States without inspection or with fraudulent 
documents, or who overstayed a nonimmigrant visa. 
6 Legal aliens include immigrants who are aliens admitted as legal permanent residents (LPRs) and nonimmigrants who 
are aliens admitted on temporary visas, including tourists, temporary workers, and foreign students.  
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removal under the INA even if they are otherwise legally present.7 For example, a legal 
permanent resident (LPR) convicted of public intoxication is not subject to removal, but an LPR 
convicted of cocaine possession is subject to removal.8 Third, a subset of these removable 
criminal aliens, aggravated felons,9 are also ineligible for most forms of relief from removal and 
ineligible to be readmitted to the United States.10  
Figure 1. Criminal and Unauthorized Aliens 
 
Source: CRS analysis of the Immigration and Nationality Act. 
Notes: Figure 1 is roughly to scale and illustrates that there are more unauthorized aliens than criminal aliens. 
Given current data constraints, CRS is unable to approximate what share of criminal aliens is unauthorized. Al  
aliens in areas with hash lines are subject to removal. 
As Figure 1 illustrates, all unauthorized aliens are potentially removable, indicated by cross-
hatches in the figure, but the majority of them have not been convicted of a crime and are 
therefore not classified as criminal aliens.11 (Unlawful presence in the United States absent 
                                                 
7 Section 237(a)(2) of the Immigration and Nationality Act (8 U.S.C. §1227 (a)(2)) enumerates a list of criminal 
offenses that make aliens subject to removal. Criminal offenses in the context of immigration law cover violations of 
federal, state, or, in some cases, foreign criminal law. See CRS Report RL32480, Immigration Consequences of 
Criminal Activity, by Michael John Garcia. 
8 8 U.S.C. §1227(a)(2)(B)(i). 
9 Aggravated felonies refer to a class of serious criminal alien offenses created per §101(a)(43) of the INA and include 
murder, drug trafficking, or illegal trafficking in firearms or destructive devices. Subsequent measures passed by 
Congress expanded the definition of aggravated felonies and created additional criminal grounds for removal. 
10 For a more exhaustive discussion, see CRS Report RL32480, Immigration Consequences of Criminal Activity, by 
Michael John Garcia. 
11 See footnote 4. 
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additional factors is a civil violation, not a criminal offense.12) The smaller circles in Figure 1 
illustrate that some criminal aliens are removable on the basis of the specific crimes committed, 
and some are also unauthorized.  
Quantifying the Criminal Alien Population  
This section presents publicly available arrest and incarceration data for criminal aliens at the 
federal, state, and local levels from 2001 through 2010.13 Following CRS’s quantification of the 
criminal alien population, the section reviews other studies that produced comparable estimates. 
Appendix B describes related data issues in greater detail.  
Federal-Level Arrest Data  
Table 1 presents data from the Department of Justice (DOJ), Bureau of Justice Statistics (BJS) on 
the number and percentage of persons arrested for federal offenses, by citizenship status, for 
2001, 2005, and 2010. Of the 179,489 persons arrested for federal offenses in 2010, 46% were 
not U.S. citizens and 16% had unknown citizenship status. The data in Table 1 also indicate that 
the proportion of noncitizens arrested for federal offenses increased across the period analyzed. 
Table 1. Persons Arrested for Federal Offenses, by Legal Status, 2001, 2005, and 2010  
 
Number of Persons 
Percent of Total 
 
 
2001 2005 2010  2001 2005 2010 
U.S. 
Citizen 
68,200 
74,985 
68,432 
 
57% 53% 38% 
Noncitizen 
41,499 
56,492 
83,024 
 
35% 40% 46% 
Status unknown 
9,197 
8,723 
28,033 
 
8% 
6% 
16% 
Total 
records 
118,896 
140,200 
179,489 
 100% 100% 100% 
Source: Bureau of Justice Statistics, Federal Justice Statistics Program website, http://bjs.ojp.usdoj.gov/fjsrc/. 
Notes: Data do not distinguish between legal noncitizens such as LPRs and unauthorized aliens.  
Most noncitizen federal arrests between 2001 and 2010 were for illegal entry. As Figure 2 
illustrates, while federal arrests with known citizenship information increased 42%, from 109,699 
to 151,456, during this period, noncitizen arrests for illegal entry—which increased noticeably 
after 2003—accounted for virtually all of this increase.14 Noncitizen arrests for all other federal 
offenses accounted for a declining share of all federal arrests, from 19% in 2001 to 5% in 2010.15 
                                                 
12 Unlawful presence is only a criminal offense when an alien is found in the United States after having been formally 
removed or after departing the U.S. while a removal order was outstanding; see CRS Report RL32480, Immigration 
Consequences of Criminal Activity, by Michael John Garcia. 
13 Individuals housed by Immigration and Customs Enforcement (ICE) are beyond the scope of this report because they 
are not officially part of the U.S. criminal justice system. This report also does not present data on convictions. 
14 Because Figure 2 does not include “status unknown” cases, figures cited in this section of the text differ from figures 
presented in Table 1.  
15 According to BJS analysts, the transition by the U.S. Marshals Service to a new prisoner tracking system beginning 
in 2008 temporarily increased the number of cases with unreported offense types. 
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The growth of illegal entry cases caused arrests of U.S. citizens to account for a declining share 
of all federal arrests (from 62% in 2001 to 45% in 2010). 
Figure 2. Federal Arrests by Citizenship Status and Type of Offense, 2001-2010 
 
 
Source: Prisoner Tracking System, U.S. Marshals Service, as reported to the Bureau of Justice Statistics, Federal 
Justice Statistics Program website, http://bjs.ojp.usdoj.gov/fjsrc/. 
Notes: Data presented are only for cases with known citizenship status. Changes in recording procedures in 
2008 resulted in a disproportionately high number of cases with missing information in 2009 and 2010. Data do 
not distinguish between legal y present noncitizens, such as legal permanent residents, and the unauthorized alien 
population. Although persons arrested may have committed more than one federal offense, only the most severe 
offense is presented by the Bureau of Justice Statistics. 
These trends may reflect changes in enforcement and prosecution policies rather than increased 
noncitizen criminality. The number of Border Patrol apprehensions has always far exceeded the 
number of arrests for illegal entry,16 and DHS and DOJ have adopted policies to seek criminal 
charges against a higher proportion of such aliens, particularly since 2005 through Operation 
Streamline and related programs.17 Increased Border Patrol appropriations during this period may 
also have resulted in a higher proportion of illegal border crossers being apprehended, and thus a 
                                                 
16 According to CRS’s analysis of DHS data, the Border Patrol apprehended an average of 921,000 removable aliens 
per year during these years, most of whom could be charged with illegal entry, though this figure (like BJS arrest data) 
includes multiple observations of the same individuals; see Office of Immigration Statistics, Yearbook of Immigration 
Statistics FY2011, Washington, DC, 2012, p. 95. 
17 Operation Streamline is a joint DOJ-DHS program to expedite criminal processing for unauthorized aliens in certain 
border districts so that a higher proportion face criminal charges; see CRS Report R42138, Border Security: 
Immigration Enforcement Between Ports of Entry, by Marc R. Rosenblum. 
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relatively larger pool of aliens who may be charged with illegal entry, though the total number of 
border apprehensions has fallen sharply since 2005.18  
Federal, State, and Local Incarceration Data 
Incarceration represents a second measure of the criminal alien population. Table 2 presents CRS 
tabulations of the total citizen and noncitizen prison and jail populations publicly reported by the 
Bureau of Justice Statistics for 2001 through 2009 and partly through 2010. Estimates of state 
and, especially, local incarcerated populations should be interpreted with caution for the reasons 
noted in Appendix B. As of June 30, 2009, however, a total of 2,353,855 prisoners (U.S. citizens 
and noncitizens) were incarcerated: 209,771 in federal prisons, 1,395,356 in state prisons, and 
748,728 in local jails (Table 2).19  
According to BJS data presented in Table 2, noncitizens comprised 7.2% of the combined 
federal, state, and local prisoner population in 2009 (the most recent year for which complete 
noncitizen data are available), including 23.6% of the federal prison population, 4.5% of the state 
prison population, and 7.8% of the local jail population. As a basis for comparison, noncitizens 
comprised 7.1% of the U.S. population in FY2009.20 
The overall noncitizen proportion of the total prisoner population increased from 6.4% in 2001, 
with most of the change reflecting the growth of the noncitizen population in local jails. Indeed, 
the noncitizen proportion of federal prisoners actually declined between 2001 and 2009 (from 
25.2% to 23.6%), as total federal incarcerations increased at a faster rate than noncitizen federal 
incarcerations.21 The noncitizens proportion of state prisoners increased slightly, growing from 
4.3% of the total state-level incarcerated population in 2001 to 4.5% in 2009.22 And the 
proportion of noncitizens among those incarcerated in local jails increased substantially, from 
6.1% in 2001 to 7.8% in 2009, as the growth rate of noncitizens in local jails far exceeded the 
native-born growth rate in such institutions.23 
 
                                                 
18 Appropriations for the Border Patrol increased by 191%, from $1.1 billion in FY2000 to $3.6 billion in FY2010. The 
20,558 CBP agents as of September 30, 2010, represented a more than doubling of staff over that decade; see CRS 
Report R41189, Homeland Security Department: FY2011 Appropriations, coordinated by Jennifer E. Lake and William 
L. Painter. Increased border enforcement also may have a deterrent effect on would-be border crossers. 
19 All incarcerations for 2010 are as of midyear. See notes to Table 2. 
20 CRS analysis of 2008 American Community Survey data. 
21 Noncitizen federal incarcerations increased 33.1% (from 36,625 to 48,740) between 2001 and 2009, as total federal 
incarcerations increased 42.1% (from 145,416 to 206,577); see Table 2. 
22 Noncitizen state incarcerations increased 19.5% (from 54,031 to 64,053) between 2001 and 2009, as total state 
incarcerations increased 13.1% (from 1.2 million to 1.4 million); see Table 2. 
23 Noncitizen local jail incarcerations increased 55.5% (from 38,558 to 59,973) between 2001 and 2009 as total local 
jail incarcerations increased 21.6% (from 631,240 to 767,434); see Table 2. 
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Table 2. Total and Noncitizen Incarcerated Population, Federal and State Prisons and Local Jails, 2001-2010 
 
 
Proportion of Noncitizen to Total 
 
Total Incarcerated Population 
Noncitizen Incarcerated Population 
Incarcerated Population 
Total 
Federal 
State 
Local 
 Total Federal 
State 
Local 
 Total Federal 
State 
Local 
 
Prisons 
Prisons 
Jails 
Prisons 
Prisons 
Jails 
Prisons 
Prisons 
Jails 
2001 
2,022,501 145,416 1,245,845 631,240  
 129,214 36,625  54,031  38,558   
  6.4%  25.2%  4.3% 
6.1% 
2002 
2,069,507 156,993 1,247,039 665,475   140,772 38,927  54,804  47,041    6.8%  24.8%  4.4% 
7.1% 
2003 
2,131,445 163,528 1,276,616 691,301   141,253 40,051  56,112  45,090    6.6%  24.5%  4.4% 
6.5% 
2004 
2,182,591 173,059 1,295,542 713,990   147,481 42,232  57,393  47,856    6.8%  24.4%  4.4% 
6.7% 
2005 
2,244,629 180,328 1,316,772 747,529   142,170 42,803  55,804  43,563    6.3%  23.7%  4.2% 
5.8% 
2006 
2,293,748 187,618 1,340,311 765,819   155,315 44,323  57,352  53,640    6.8%  23.6%  4.3% 
7.0% 
2007 
2,350,119 193,046 1,376,899 780,174   160,583 44,734  55,766  60,083    6.8%  23.2%  4.1% 
7.7% 
2008 
2,383,778 199,618 1,398,627 785,533   163,774 45,756  64,687  53,331    6.9%  22.9%  4.6% 
6.8% 
2009 
2,384,912 206,577 1,410,901 767,434  
 172,766 48,740  64,053  59,973   
  7.2%  23.6%  4.5% 
7.8% 
2010 
2,353,855 209,771 1,395,356 748,728    N/A  47,569 
N/A 
N/A    N/A  22.7%  N/A 
N/A 
Sources: Total federal and state prison population figures: BJS, Prison Inmates at Midyear 2009-Statistical Tables report, Table 1; Noncitizen federal prison 
figures: BJS Federal Criminal Case Processing Statistics online, http://bjs.ojp.usdoj.gov/fjsrc/; Noncitizen state prison figures: BJS National Prison Statistics (NPS) 
program reported in Sourcebook of Criminal Justice Statistics, 2009, Table 6.42.2009; Total local jail figures: BJS Jail Inmates at Midyear 2010-Statistical Tables report, Table 1. 
Local jails’ number of noncitizens are derived by CRS from data on the proportion of noncitizens to total number of inmates presented in the Jail Inmates at Midyear 2007 
report online, http://bjs.ojp.usdoj.gov/content/pub/pdf/jim07.pdf, for 2001 through 2007 and computed by CRS using the Annual Survey of Jails microdata files downloaded 
from ICPSR’s website, http://www.icpsr.org, for 2008 and 2009. 
Notes: Federal and state total prison population figures and federal noncitizen population figures are measures of the incarcerated population as of December 31 
of each year—except for 2010, which are measures of the incarcerated population as of June 30. They include inmates under jurisdiction of federal or state prisons or in 
the custody of federal or state prisons or local jails. (Jurisdiction refers to prisoners under the legal authority of state and federal correctional officials, regardless of where a 
prisoner is held. Custody refers to the number of inmates held in state or federal prisons or local jails, regardless of sentence length or the authority having jurisdiction.) 
State noncitizen prison and local jail population figures are measures of the incarcerated population as of June 30 for each year. Because total counts of noncitizens in 
local jails are not available for many reporting local jurisdictions, CRS imputed the noncitizen local jail figures by multiplying the total local jails figures by the percentages of 
noncitizens in local jails obtained from the Annual Survey of Jails (noted in sources above). In 2008, the difference between mid-year and end-year figures at both the federal 
and state levels was less than 0.1%. As of December 11, 2012, figures shown in Table 2 for the noncitizen incarcerated population were the most current available. 
 
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Table 3 illustrates the types of crimes for which apprehended criminals were sentenced to federal 
prison in 2001, 2005, and 2010. It presents data from the U.S. Sentencing Commission by 
citizenship status and grouped into three categories: violent crimes, nonviolent crimes, and 
immigration crimes. The data indicate that for all three years shown, violent crimes made up less 
than 1% of all crimes committed by criminal aliens, compared to 5%-6% of all crimes committed 
by citizens. For noncitizens, immigration crimes grew as a proportion of total federal offenses for 
which they received sentences, increasing from 47.3% of all crimes in 2001 to 69.4% by 2010. 
For citizens, by contrast, immigration crimes made up less than 5% of all crimes for citizens in 
any of the three years shown. Moreover, the citizen proportion of crime categories changed 
relatively little over the three years shown.  
Table 3. Offense Category of Sentenced Offenders, by Citizenship, 2001-2010 
 
2001 
 
2005 
 
2010 
 
Citizen Noncitizen  Citizen Noncitizen  Citizen Noncitizen 
Violent 
crimes  6.3% 0.5% 
 
5.4% 0.5% 
 
5.0% 0.4% 
Nonviolent 
crimes 
91.2% 52.2%  
90.6% 39.4%  
91.6% 30.2% 
Immigration 
crimes 
2.6% 47.3% 
 
4.1% 60.1% 
 
3.4% 69.4% 
Total 
100% 100%  
100% 100%  
100.0% 
100.0% 
Source: CRS analysis of data from the 2001, 2005, and 2010 Sourcebook of Federal Sentencing Statistics, Table 9, 
United States Sentencing Commission.  
Notes: Violent crimes include murder, manslaughter, kidnapping, sexual abuse, assault, robbery, and arson. 
Immigration crimes include alien smuggling, unlawful entering or remaining in the United States, trafficking in 
immigration documents or making false or fraudulent immigration statements, and acquiring fraudulent 
immigration documents. Nonviolent crimes refer to all other offenses.  
Estimates from the American Community Survey 
The U.S. Census American Community Survey (ACS) represents an additional source of 
information that can be used to corroborate CRS’s computations of the criminal alien population. 
The ACS is conducted continuously and yields annual estimates on the size and characteristics of 
the U.S. population, including a measurement of persons living in institutions, or “group 
quarters,” which includes correctional facilities as well as juvenile facilities, nursing facilities, 
and other health care facilities.24 Although the ACS Public Use Microdata Sample does not 
distinguish among these various types of institutions, it can be used to derive an estimate of the 
criminal alien population by selecting characteristics of persons within the institutionalized 
population that would be most likely to indicate such persons were inmates incarcerated in 
correctional facilities rather than patients living in health or long-term care facilities. These 
characteristics include persons ages 18 to 55, living in group quarters, who were noncitizens.25  
                                                 
24 The annual ACS sample is approximately 3 million addresses, and data are collected from roughly one-twelfth of the 
sample each month. The survey is mandatory, and interviews are conducted via mail, telephone, or personal visits. 
25 This estimate relies on parameters derived from a recent U.S. Census analysis; see Stephanie Ewert and Tara 
Wildhagen, Educational Characteristics of Prisoners: Data from the ACS, U.S. Census Bureau, Housing and 
Household Economic Statistics Division, SEHSD Working Paper #2011-8, Washington, DC, March 31, 2011. 
According to Ewert and Wildhagen, correctional facilities accounted for 93% of persons ages 18-55 living in such 
(continued...) 
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According to these data, 2,312,031 persons were living in group quarters in 2010, most of which 
consisted of correctional facilities. This figure closely matches the 2,266,832 figure produced by 
the Bureau of Justice Statistics for the same year.26 Of this estimated criminal population, the 
analysis of ACS data yields an estimate for the noncitizen incarcerated population (between ages 
18-55) of 165,855, or 7.17% of the total—an estimate roughly comparable to CRS’s overall 
figure for 2009 (the most recent figure available) of 172,766 (Table 2). ACS data do not 
distinguish between federal, state, and local institutions. 
Other Estimates of the Criminal Alien Population 
While relatively few studies have attempted to quantify the criminal alien population,27 a body of 
evidence suggests that the foreign born are less likely to commit crimes28 and less likely to be 
incarcerated than the native born.29 For instance, a 2007 study estimated that the foreign born 
(including noncitizens and naturalized citizens) made up 35% of California’s adult population but 
only 17% of its adult prison population.30 When the analysis expands to include all correctional 
institutions (not only prisons but also jails, halfway houses, and similar facilities) and to focus on 
the sub-population most likely to commit crimes (males between ages 18-40) the difference 
increases, with native-born institutionalization rates 10 times those of the foreign born.31  
While these studies confront methodological challenges similar to those discussed in Appendix 
B, they suggest that the noncitizen proportion among all U.S. criminals (i.e., the criminal alien 
population) likely is no more than—and possibly is below—the foreign-born proportion of the 
total U.S. population, or 12.9% as of 2010. This rate would suggest an upper bound estimate for 
the incarcerated criminal alien population of 303,600, based on a total incarcerated population of 
2,353,855 (from Table 2).  
                                                                  
(...continued) 
group quarters. 
26 U.S. Department of Justice, Bureau of Justice Statistics, Sourcebook of Criminal Justice Statistics Online, 
Washington, DC 2010, http://www.albany.edu/sourcebook/pdf/t612010.pdf. 
27 See, for example, John Scalia and Marika F. X. Litras, Immigration Offenders in the Federal Criminal Justice 
System, 2000, Bureau of Justice Statistics, Washington, DC, August 2002; A. Wunder, “Foreign Inmates in U.S. 
Prisons: An Unknown Population,” Corrections Compendium, vol. 20, no. 4 (April 1995), pp. 4-18. Foreign born here 
refers to both noncitizens and naturalized citizens 
28  See, for example, Kristin F. Butcher and Anne Morrison Piehl, “Cross-City Evidence on the Relationship Between 
Immigration and Crime,” Journal of Policy Analysis and Management, vol. 17, no. 3 (Summer 1998), pp. 457-493; 
John Hagan and Alberto Palloni, “Sociological Criminology and the Mythology of Hispanic Immigration and Crime,” 
Social Problems, vol. 46, no. 4 (1999), pp. 617-632; Lesley Williams Reid, Harald E. Weiss, and Robert M. Adelman, 
et al., “The Immigration–Crime Relationship: Evidence Across U.S. Metropolitan Areas,” Social Science Research, 
vol. 34, no. 4 (December 2005), pp. 757-780. 
29  See, for example, Ruben G. Rumbaut, Roberto G. Gonzales, and Golnaz Komaie, et al., “Immigration and 
Incarceration: Patterns and Predictors of Imprisonment among First-and Second-Generation Young Adults,” in 
Immigration and Crime: Race, Ethnicity and Violence, ed. Ramiro Martinez Jr. and Abel Valenzuela Jr. (New York: 
New York University Press, 2006), pp. 64-89; and Kristin F. Butcher and Anne Morrison Piehl, Why Are Immigrants’ 
Incarceration Rates so Low? Evidence on Selective Immigration, Deterrence, and Deportation, National Bureau of 
Economic Research, NBER Working Paper 13229, Cambridge, MA, July 2007, http://www.nber.org/papers/w13229. 
30 Kristin F. Butcher, Anne Morrison Piehl, and Jay Liao, Crime, Corrections, and California: What Does Immigration 
Have to Do with It?, California Counts: Population Trends and Profiles, San Francisco, CA, February 2008, 
http://www.ppic.org/content/pubs/cacounts/CC_208KBCC.pdf. 
31 Ibid. 
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In 2011, the Government Accountability Office (GAO) estimated the U.S. criminal alien 
population in federal prisons and criminal alien incarcerations for state prisons and local jails.32 
To enumerate the federal prison population, GAO used Bureau of Prison (BOP) data, which are 
considered relatively reliable and are collected consistently.33 To undertake the more challenging 
task of enumerating the criminal alien population in state prisons and local jails, GAO relied on 
data from the Department of Justice’s State Criminal Alien Assistance Program (SCAAP).34 
SCAAP data provide a direct count of cases for which state and local jurisdictions seek 
reimbursement for correctional officer salary costs incurred for incarcerating “undocumented 
criminal aliens” and thus provide an alternative method for estimating the criminal alien 
population to that presented by CRS above. However, because of the way SCAAP data are 
recorded, they do not accurately reflect the incarcerated criminal alien population at a given point 
in time.35 Based on these sources, GAO reported 52,929 criminal aliens in federal prisons, and 
91,823 state prison and 204,136 local jail SCAAP incarcerations in 2009.36 
Incarceration of the criminal alien population over the past decade has occurred within the 
context of a foreign-born population that grew from 31.5 million to 39.9 million between 2001 
and 2010.37 While their 2010 proportion of the U.S. population amounted to 12.9%, the foreign 
born accounted for 32.0% of all U.S. population growth from 2001 to 2010 because their numbers 
grew more rapidly than those of the native born.38 Figure 3 illustrates this demographic context 
                                                 
32 U.S. Government Accountability Office, Criminal Alien Statistics: Information on Incarcerations, Arrests, and 
Costs, GAO-11-187, March 24, 2011. Note that “the U.S. criminal alien population” refers to unique individuals, while 
“criminal alien incarcerations” refers to unique incarcerations that may involve the same individuals being incarcerated 
multiple times. In addition, the Senate Appropriations Committee reported in 2009 that “ICE extrapolated from various 
sources and estimated that there are about 300,000 to 450,000 criminal aliens, who are available for removal, detained 
each year at Federal, State, and local prisons and jails,” though the Committee report does not explain the methodology 
behind this estimate; see U.S. Congress, Senate Committee on Appropriations, Subcommittee on Department of 
Homeland Security, Department of Homeland Security Appropriations Bill, 2009, Report to accompany S. 3181, 110th 
Cong., 2nd sess., June 23, 2008, S.Rept. 110-396 (Washington: GPO, 2008), p. 49. 
33 See Appendix B for more information on the presentation of publicly available data. 
34 SCAAP reimburses states and localities for correctional officer salary costs incurred for incarcerating 
“undocumented criminal aliens” under certain circumstances. For more information on SCAAP, see CRS Report 
RL33431, Immigration: Frequently Asked Questions on the State Criminal Alien Assistance Program (SCAAP), by 
Karma Ester. Also see GAO, Criminal Alien Statistics. 
35 SCAAP data may not be representative of the U.S. criminal alien population for at least three reasons. First, 
reimbursement rules prevent SCAAP data from accurately capturing certain groups of individuals, including legal 
permanent residents, persons jailed for less than four days, and persons with only one misdemeanor. Second, not all 
states and eligible localities participate in the program equally. Those with higher costs, such as metropolitan 
jurisdictions that process large numbers of unauthorized aliens are more likely to do so than smaller localities. Third, 
individuals may be double-counted because they may appear in more than one jurisdiction if they are processed in 
several places for the same offense, for instance in a local jail and a state prison, or in different states. Such double 
counting may explain the sizable differences in the state and local criminal alien SCAAP incarcerations reported by 
GAO and the number of criminal aliens incarcerated in state prisons and local jails produced in this report, which relies 
exclusively on BJS data. In addition to the 2011 GAO report cited above, see also U.S. Government Accountability 
Office (GAO), Information on Criminal Aliens Incarcerated in Federal and State Prisons and Local Jails, GAO-05-
337R, April 7, 2005. 
36 U.S. Government Accountability Office, Criminal Alien Statistics: Information on Incarcerations, Arrests, and 
Costs, GAO-11-187, March 24, 2011. 
37 To obtain a consistent series across individual years for Figure 3 and corresponding text, CRS used figures obtained 
from the Statistical Abstract of the United States, a reference guide published by the U.S. Census Bureau. Such figures 
were computed by the Census Bureau using the Current Population Survey (CPS) which produces estimates of the 
foreign born that are lower than those from the ACS. For instance, the ACS estimate of the foreign-born population for 
2009 was 38.5 million. 
38 Moreover, these figures do not include an estimated 13.9 million native-born children born to at least one foreign-
(continued...) 
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for the criminal alien population growth (shown in Table 2) and the close correspondence 
between CRS’s calculation of the proportion of noncitizens in the total prison population and the 
foreign-born population overall. Such trends receive empirical support from academic studies 
reviewed above and from the ACS. 
Figure 3. Proportion of the U.S. and Incarcerated Population by Nativity and 
Citizenship, 2001-2009 
 
Source: Total foreign born, noncitizen foreign born, and U.S. population figures: U.S. Census Bureau, Statistical 
Abstract of the United States (various years); Noncitizen proportion of incarcerated population, see Table 2. 
Note: As of December 2012, published figures from 2009 remain the most up-to-date available on the 
noncitizen proportion of the total incarcerated population.  
Nationally, incarcerated persons represent roughly one-third of the total correctional population, 
with persons on probation and parole comprising the other two-thirds.39 As with all persons in the 
correction population, the relatively larger pool of noncitizens initially interacting with the 
criminal justice system is filtered down to a smaller population whose crimes are judged to merit 
prosecution and incarceration.  
History of Criminal Alien Removal Programs  
In 1986, with passage of the Immigration Reform and Control Act (P.L. 99-603), Congress made 
deporting aliens who had been convicted of certain crimes an enforcement priority. The law 
                                                                  
(...continued) 
born parent. See CRS Report R41592, The U.S. Foreign-Born Population: Trends and Selected Characteristics, by 
William A. Kandel, pp. 14-16. 
39 In 2010, the total year-end correctional population numbered 7,076,200, with 4,055,514 persons on probation, 
2,262,832 persons incarcerated, and 840,676 persons on parole. See Sourcebook of Criminal Justice Statistics Online, 
Table 6.1.2010, http://www.albany.edu/sourcebook/pdf/t612010.pdf. 
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required the Attorney General “In the case of an alien who is convicted of an offense which 
makes the alien subject to deportation … [to] begin any deportation proceeding as expeditiously 
as possible after the date of the conviction.”40 
The former Immigration and Naturalization Service (INS) established a pair of programs in 1988 
to comply with this requirement: the Institutional Removal Program (IRP) and the Alien Criminal 
Apprehension Program (ACAP).41 The programs forged partnerships with corrections facilities to 
identify deportable aliens convicted of crimes before their release from jail or prison. They also 
worked with the Department of Justice Executive Office for Immigration Review to initiate 
deportation proceedings against aliens serving sentences for deportable offenses during their 
period of incarceration.42 
The IRP and ACAP focused initially on aggravated felons, a class of serious criminal aliens 
created in immigration law by the Anti-Drug Abuse Act of 1988 (P.L. 100-690) and enumerated 
in §101(a)(43) of the INA. The Anti-Drug Abuse Act defined aggravated felonies to include 
aliens convicted of murder, drug trafficking, or illegal trafficking in firearms or destructive 
devices. Between 1990 and 1996, Congress enacted a series of measures, including the Illegal 
Immigrant Reform and Immigrant Responsibility Act of 1996 (P.L. 104-208, Division C), that 
expanded the definition of aggravated felons and created additional criminal grounds for 
removal.43 The mandates of the IRP and ACAP likewise expanded to include this broader list of 
criminal immigration offenses. 
In 1999, the INS issued an Interior Enforcement Strategy, which named as the agency’s top 
interior enforcement priority the identification and removal of criminal aliens and the 
minimization of recidivism (i.e., illegal reentry by previously removed aliens).44 Accordingly, 
between 1998 and 2002, the INS devoted more resources to the removal of criminal aliens than to 
all other interior enforcement priorities combined.45 Nonetheless, INS failed to identify and 
remove all criminal aliens.46  
                                                 
40 P.L. 99-603, §701. 
41 Prior to the enactment of the Homeland Security Act of 2002 (P.L. 107-296), immigration enforcement activities 
were primarily the responsibility of the Immigration and Naturalization Service (INS) within the Department of Justice. 
The INS was dissolved on March 1, 2003 and made part of the Department of Homeland Security (DHS). 
42 The Institutional Removal Program, originally known as the Institutional Hearing Program, focused on a small 
number of federal and state prisons that held the largest number of criminal aliens; the Alien Criminal Apprehension 
Program covered other jails and prisons. 
43 Immigration Act of 1990, P.L. 101-649 (1990); Immigration and Nationality Technical Correction Act of 1994, P.L. 
103-416 (1994); Antiterrorism and Effective Death Penalty Act of 1996, P.L. 104-132 (1996); Illegal Immigrant 
Reform and Immigrant Responsibility Act of 1996, P.L. 104-208, Div. C (1996). See CRS Report RL32480, 
Immigration Consequences of Criminal Activity, by Michael John Garcia. 
44  U.S. General Accounting Office, Homeland Security: Challenges to Implementing the Immigration Interior 
Enforcement Strategy, GAO-03-660T, April 2003.  
45 Ibid. 
46  CRS Report RL33351, Immigration Enforcement Within the United States, coordinated by Alison Siskin; GAO, 
Challenges to Implementing the Immigration Interior Enforcement Strategy. 
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ICE Programs Targeting Criminal Aliens 
In the wake of the September 11 attacks, the new Department of Homeland Security (DHS) 
focused its enforcement activities on suspected terrorists and homeland defense, but with the 
continued growth of the foreign-born population after 2000, programs targeting criminal aliens 
also remained an enforcement priority. Within DHS, the IRP and ACAP initially were managed 
jointly by Immigration and Customs Enforcement’s (ICE) Detention and Removal Operations 
(DRO) (renamed Enforcement and Removal Operations (ERO) in 2010) and its Office of 
Homeland Security Investigations. Between 2005 and 2007, the IRP and ACAP were combined 
into a single program within DRO now known as the Criminal Alien Program.47 ICE currently 
operates four programs wholly or partly focused on criminal aliens (discussed in more detail 
below): the Criminal Alien Program (CAP), Secure Communities, the §287(g) program, and the 
National Fugitive Operations Program (NFOP). 
These programs operate at several different points in the criminal justice process, and in some 
cases at more than one point (Figure 4). The CAP, Secure Communities, and certain §287(g) 
programs are “jail enforcement” programs that screen individuals for possible immigration 
violations and for criminal-related grounds for removal in federal and state prisons and local jails. 
Most individuals screened by jail enforcement programs are arrested by state or local officers, not 
ICE agents, for reasons unrelated to immigration law.48  
Figure 4. ICE Enforcement and Removal Programs in the Criminal Justice Process 
 
Source: CRS analysis of ICE enforcement programs. 
Notes: CAP refers to the Criminal Alien Program; NFOP refers to the National Fugitive Operations Program; 
287(g) refers to agreements entered pursuant to INA §287(g) for jailing screening or task force programs. NA 
indicates “not applicable.” 
                                                 
47 See U.S. Congress, Senate Committee on the Judiciary, Subcommittee on Immigration, Border Security, and 
Citizenship, Strengthening Interior Enforcement: Deportation and Related Issues, testimony of Department of 
Homeland Security Acting Director of Detention and Removal Operations, U.S. Immigration and Customs 
Enforcement Victor Cerda, 109th Cong., 1st sess., April 14, 2005. 
48 See U.S. Department of Homeland Security Advisory Council, “Task Force on Secure Communities Findings and 
Recommendations,” September 2011, p. 4. (Hereinafter DHS Secure Communities Task Force Report.) 
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Jail enforcement programs conduct immigration-related screening at two main points (Figure 4). 
First, all three of ICE’s jail enforcement programs conduct screening as individuals are being 
booked into jail. The booking process occurs after an arrest but before an arrestee faces specific 
criminal charges and typically involves the creation of a biometric record (i.e., capturing 
photographs and fingerprints). Second, CAP also conducts immigration-related screening later in 
the criminal justice processing, focusing on individuals who have been convicted of crimes and 
are incarcerated.  
In addition to these jail enforcement programs, two ICE “task force” programs are wholly or 
partly targeted at criminal aliens outside of jails and prisons.49 ICE’s NFOP targets at-large 
criminal aliens, including fugitive aliens who have not been convicted of a crime (i.e., prior to 
entering the criminal justice process) and aliens who have been convicted of crimes and 
subsequently released from prison (i.e., at the end of the process; see Figure 4). Certain §287(g) 
programs also include task forces, though most §287(g) task forces are not primarily focused on 
criminal aliens, as discussed below. Compared to the jail enforcement programs, these task force 
programs arrest far fewer removable aliens, though they include a higher proportion of high-
priority cases (see “Enforcement Statistics”). 
Jail Enforcement Programs  
Criminal Alien Program (CAP) 
The Criminal Alien Program (CAP) is an umbrella program that includes several different 
systems for identifying, detaining, and initiating removal proceedings against criminal aliens 
within federal, state, and local prisons and jails. According to ICE, “CAP aims to identify all 
foreign born nationals incarcerated in jails and prisons in the United States” by interviewing 
aliens and screening their biographic information against DHS databases. CAP’s mission is to 
prevent the release of criminal aliens from jails and prisons into the United States by securing 
final orders of removal prior to the termination of aliens’ criminal sentences and to ensure that 
aliens are transferred into ICE custody to be removed from the United States upon completion of 
their criminal sentences.50 
CAP’s primary jail enforcement program includes 126 ten-person teams that are assigned to 
federal, state, and local prisons and jails throughout the country to conduct screening operations 
both during booking and among incarcerated prisoners.51 In addition to onsite deployment of ICE 
officers and agents, CAP uses video teleconference (VTC) equipment that connects jails and 
prisons to ICE’s Detention Enforcement and Processing Offenders by Remote Technology 
(DEPORT) Center in Chicago, IL.52 CAP also works with state and local correctional departments 
                                                 
49 ICE also operates the Joint Criminal Alien Removal Task Force (JCART) program, located within CAP and 
established in 2009. The JCART pursues known at-large criminal aliens, including in particular aliens who have been 
convicted of drug trafficking offenses, violent crimes, and sex offenses and are subsequently released from federal, 
state or local custody. JCART is an inter-agency program that (in addition to ICE) includes other DHS enforcement 
branches, probation and parole offices, the United States Marshals Service, the Bureau of Prisons, and local law 
enforcement agencies. See ICE, “Fact Sheet: Criminal Alien Program,” http://www.ice.gov/news/library/factsheets/
cap.htm.  
50  ICE, Fact Sheet: Criminal Alien Program, March 29, 2011, http://www.ice.gov/news/library/factsheets/cap.htm. 
51 ICE, Congressional Budget Justifications FY2012. 
52 ICE, Secure Communities: Quarterly Report FY2010, 4th Quarter, January 3, 2011, http://www.ice.gov/doclib/foia/
(continued...) 
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that provide ICE with inmate rosters. ICE analyzes roster data and compares prisoner data to 
immigration databases. According to ICE, CAP screening systems together with Secure 
Communities (discussed below) will cover 100% of the country’s jails and prisons by the end of 
FY2013.53 
Additionally, the CAP program includes several specialized programs related to criminal aliens.54 
CAP’s Violent Criminal Alien Section works with U.S. Attorneys to pursue criminal cases against 
high-priority criminal offenders identified by CAP officers. CAP’s Rapid Removal of Eligible 
Parolees program works with state law enforcement agencies to identify incarcerated criminal 
aliens eligible for parole and facilitates their early release along with the ensured removal from 
the United States. CAP maintains a special partnership with Phoenix-area law enforcement 
agencies (LEAs) through the Phoenix Law Enforcement Area Response program. Under this 
program, CAP officers are to respond to 100% of Arizona LEA requests 24 hours a day, 7 days a 
week, which resulted in more than 1,700 arrests in FY2011.55 CAP also maintains a task force 
program, the Joint Criminal Alien Removal Taskforces, which identifies and arrests high-priority 
at-large convicted criminal aliens.  
Secure Communities  
Secure Communities is an information sharing program between the Departments of Justice and 
Homeland Security that uses biometric data to screen for removable aliens as people are being 
booked into jails. Under the program, when participating law enforcement agencies submit the 
fingerprints of arrestees to the Federal Bureau of Investigation (FBI) for criminal background 
checks, the fingerprints also are automatically checked against DHS databases, and potential 
matches are forwarded to ICE’s Law Enforcement Support Center (LESC).56 ICE agents at the 
LESC confirm the identity of matched prints and screen their records for immigration violations 
and criminal histories. When the LESC determines that the arrestee may be a removable alien, the 
LESC evaluates the alien’s criminal history and notifies the ICE Enforcement and Removal field 
office in the arresting jurisdiction about the match. 
After being notified that a removable alien has been arrested, the local ICE field office supervisor 
reviews the record and decides how to proceed based on the priority attached to the case (see 
“DHS Enforcement Priorities and Discretion”) and the office’s available resources. If the office 
decides to initiate removal proceedings against an alien, ICE normally issues an immigration 
detainer. The detainer is a request that the arresting agency hold the alien following completion of 
his or her criminal proceeding for up to 48 hours (excluding holidays and weekends) to allow ICE 
                                                                  
(...continued) 
secure_communities/congressionalstatusreportfy104thquarter.pdf. 
53 ICE, Congressional Budget Justifications FY2013, p. 51.  
54 For more information on the Criminal Alien Program, see ICE, “Fact Sheet: Criminal Alien Program,” 
http://www.ice.gov/news/library/factsheets/cap.htm. 
55 ICE, Congressional Budget Justifications FY2013, p. 50. 
56 The Law Enforcement Support Center (LESC) is ICE’s national point of contact for local, state, and federal law 
enforcement agencies, corrections systems, and court systems seeking information about aliens suspected, arrested, or 
convicted of criminal activity. The LESC staffs a 24-hour phone line to respond to queries, and provides customs, 
immigration, and identity information based on ICE records. See ICE, “Law Enforcement Support Center,” 
http://www.ice.gov/lesc/. 
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CAP officers to take custody of the alien and to initiate removal proceedings.57 In contrast with 
the other ICE programs discussed in this report, Secure Communities does not include an 
enforcement component per se; removable aliens identified through Secure Communities and 
identified as enforcement priorities are arrested and placed in removal proceedings by ICE agents 
operating outside of Secure Communities, typically including agents from the CAP program or 
agents from §287(g) jail screening programs.  
§287(g) Jail Screening Program  
Section 287(g) of the INA permits the delegation of certain immigration enforcement functions to 
state and local law enforcement agencies. Agreements entered pursuant to INA §287(g) 
(commonly referred to as §287(g) agreements) enable specially trained state or local officers to 
perform specific functions relating to the investigation, apprehension, or detention of aliens, 
during a predetermined time frame and under federal supervision.58 Although §287(g) agreements 
were authorized as part of the 1996 Illegal Immigration Reform and Immigrant Responsibility 
Act (P.L. 104-208, Div. C, IIRIRA), the first §287(g) agreement was implemented in 2002, and 
50 of the 57 current §287(g) agreements as of December 2012 were signed after 2006.59 
More than half (32 of 57) of the §287(g) agreements identified in December 2012 are jail 
enforcement agreements.60 Under these agreements, specially trained officers within state and 
local corrections facilities are authorized to identify criminal aliens by interviewing them and 
screening their biographic information against the same DHS databases used by CAP agents and 
officers. Section 287(g) officers also use ICE’s database and Enforcement Case Tracking System 
(known as ENFORCE) to enter information about the alien and to generate the paperwork for an 
immigration detainer and a Notice to Appear (initiating the formal removal process). State and 
local corrections officers are supervised by CAP agents or other ICE Enforcement and Removal 
Office agents. 
Task Force Programs  
§287(g) Task Force Program 
Seventeen of the current §287(g) agreements are for task force programs.61 In these programs, 
designated law enforcement officers may, during the course of their regular law enforcement 
duties within the community or under the direction of a supervising federal immigration officer, 
identify and arrest certain removable aliens on immigration charges.62 In cooperation with local 
                                                 
57 The regulations governing immigration detainers are found at 8 C.F.R. 287.7; also see CRS Report R42690, 
Immigration Detainers: Legal Issues, by Kate M. Manuel. 
58 INA §287(g)(5), 8 U.S.C. §1357(g)(5); see CRS Report R41423, Authority of State and Local Police to Enforce 
Federal Immigration Law, by Michael John Garcia and Kate M. Manuel. 
59 ICE, “Fact Sheet: Delegation of Immigration Authority Section 287(g) Immigration and Nationality Act,” 
http://www.ice.gov/news/library/factsheets/287g.htm#signed-moa. 
60 Ibid. 
61 ICE, “Fact Sheet: Delegation of Immigration Authority Section 287(g).” 
62 See CRS Report R41423, Authority of State and Local Police to Enforce Federal Immigration Law, by Michael John 
Garcia and Kate M. Manuel. 
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ICE Homeland Security Investigations offices,63 the §287(g) task force programs pursue a variety 
of specific law enforcement targets, including document fraud, human smuggling, and drug 
enforcement. 
In addition to jail enforcement and task force models, eight of the current §287(g) programs are 
“hybrid” programs that include jail enforcement agreements as well as task forces within the 
same jurisdiction. 64 For hybrid programs, ICE Enforcement and Removal agents supervise the 
jail enforcement programs and Homeland Security Investigations agents supervise the task force 
operations. 
National Fugitive Operations Program  
The National Fugitive Operations Program (NFOP) pursues known at-large criminal aliens and 
fugitive aliens. ICE created the NFOP in 2003 to expand the agency’s ability to locate, arrest, and 
remove fugitive aliens, defined as aliens who have “failed to leave the United States based upon a 
final order of removal, deportation or exclusion, or who [have] failed to report to ICE after 
receiving notice to do so.”65 In 2009, with support from Congress,66 the NFOP expanded its focus 
to locating, arresting, and removing at-large convicted criminal aliens, aliens who pose a threat to 
national security and community safety, members of transnational gangs, child sex offenders, and 
aliens with prior convictions for violent crimes.67 
The NFOP consists of 104 fugitive operations teams that use data from the National Crime 
Information Center (NCIC)68 and other intelligence sources to pursue criminal aliens and other 
NFOP priority cases. Based on these leads, NFOP teams conduct enforcement actions at 
worksites, in residential areas, and at other locations.  
Differences Among Criminal Alien Enforcement Programs  
Table 4 summarizes key differences among ICE’s four main programs targeting criminal aliens. 
One core distinction is between jail enforcement programs—including CAP, Secure 
Communities, and most §287(g) programs—and task force programs—including NFOP and 17 
                                                 
63 ICE Homeland Security Investigations (HSI) directorate oversees ICE’s criminal investigations covering 
immigration crime, human rights violations and human smuggling, smuggling of narcotics, weapons and other 
contraband, financial crimes, cybercrime, and export enforcement issues; see ICE, “ICE Homeland Security 
Investigations,” http://www.ice.gov/about/offices/homeland-security-investigations/. 
64 Ibid. and ICE, “Fact Sheet: Delegation of Immigration Authority Section 287(g).”  
65 ICE, “Fact Sheet: ICE Fugitive Operations Program,” http://www.ice.gov/news/library/factsheets/fugops.htm. 
66 In 2009, House appropriators moved the NFOP from the general Detention and Removal Operations budget to 
include it among a set of programs for the Identification and Removal of Criminal Aliens; see U.S. Congress, House 
Committee on Appropriations, Subcommittee on Homeland Security, Department of Homeland Security 
Appropriations Bill, 2009, Report to Accompany H.R. 6947, 110th Cong., 2nd sess., September 18, 2008, H.Rept. 110-
862 (Washington: GPO, 2008), pp. 51-53. 
67 ICE, “Fact Sheet: ICE Fugitive Operations Program,” 
68 The National Crime Information Center (NCIC) is the Federal Bureau of Investigation’s (FBI) national clearinghouse 
of crime data, including 12 person files including Supervised Release, National Sex Offender Registry, Foreign 
Fugitive, Immigration Violator, Missing Person, Protection Order, Unidentified Person, U.S. Secret Service Protective, 
Gang, Known or Appropriately Suspected Terrorist, Wanted Person, and Identity Theft. NCIC includes 15 million 
active records and averages 7.5 million transactions per day. See FBI, “National Crime Information Center,” 
http://www.fbi.gov/about-us/cjis/ncic. 
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§287(g) programs. By their nature, jail enforcement programs are not highly targeted: they are 
designed to screen the entire population of people passing through the criminal justice system. 
Those screened by jail enforcement programs are typically arrested by state and local law 
enforcement agents for non-immigration offenses. 
Conversely, task force programs tend to be more targeted operations, pursuing specific serious 
criminal aliens, fugitive aliens, or other criminals who have been targeted by ICE or other law 
enforcement agencies. Under task force operations, ICE agents or other law enforcement officers 
with specific immigration training are the arresting agents. 
Table 4. ICE’s Primary Criminal Alien Enforcement Programs  
 
Jail Enforcement Programs 
Task Force Programs  
 CAP 
Secure 
§287(g)—Jail 
§287(g)—
Communities  Enforcement 
Task Force 
NFOP 
Who makes the 
State or local 
LEA 
LEA 
ICE or LEA, 
ICE  
arrest? 
law 
with ICE 
enforcement 
training and 
agent (LEA) 
supervision 
Who conducts 
ICE  
ICE  
LEA, with ICE 
ICE or LEA, 
ICE  
the immigration 
training and 
with ICE 
screening or 
supervision 
training and 
selects the 
supervision 
enforcement  
target? 
When does 
During 
During  
During 
Pre-arrest 
Pre-arrest 
immigration  
booking and 
booking  
booking  
through 
through post-
screening/ 
post-conviction 
booking  
release 
targeting occur? 
How many 
More than 
3,074 
40 jurisdictions  25 jurisdictions  104 teams 
jurisdictions/ 
1,200 CAP 
jurisdictions in 
in 19 states 
in 13 states 
task forces are 
officers 
50 states 
operating?a  
monitor over 
4,300 facilities 
Source: CRS Analysis of ICE programs. Secure Communities jurisdictions data as of August 22, 2012, from ICE, 
“Activated Jurisdictions,” http://www.ice.gov/doclib/secure-communities/pdf/sc-activated.pdf; §287(g) jurisdictions 
data as of October 16, 2012, from ICE, “287(g) Results and Participating Entities,” http://www.ice.gov/news/
library/factsheets/287g.htm#signed-moa.  
Notes: CAP refers to the Criminal Alien Program; NFOP refers to the National Fugitive Operations Program; 
287(g) refers to agreements entered pursuant to INA §287(g) for jailing screening or task force programs; LEA 
refers to law enforcement agent; ICE refers to the U.S. Immigration and Customs Enforcement agency. 
a.  Number of jurisdictions as of March 2012 for CAP, August 2012 for Secure Communities, October 2012 
for the §287(g) program, and March 2012 for NFOP. The reported number of §287(g) task forces counts 8 
hybrid programs as both jail enforcement and task force models; as of October 13, 2011, ICE has §287(g) 
agreements with a total of 57 law enforcement agencies in 21 states.  
A second, related difference concerns who conducts immigration-related screening and who 
selects targets for immigration-related enforcement. Under all but the §287(g) program, ICE 
agents conduct immigration screening either in the jail (under CAP) or remotely (under CAP and 
Secure Communities); and ICE and DHS select the targets for task force operations based on at-
large aliens’ criminal records and immigration histories. Under the §287(g) program, local 
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corrections officers with ICE training conduct immigration screenings during the booking process 
(for jail programs), and local law enforcement agencies exercise some discretion about when and 
how to participate in immigration-related task force enforcement activities. 
These ICE programs also target criminal aliens at different points in the criminal justice process, 
as noted above and summarized in Table 4. All three jail enforcement programs conduct 
screening during the booking process, meaning that many potentially removable aliens are 
identified even though they have never been charged with or convicted of a crime. (As noted 
above, unauthorized aliens are potentially removable regardless of whether they are eventually 
convicted of a criminal offense. Certain legal aliens only become removable if they are charged 
and convicted of a removable criminal offense.) CAP also conducts screening of persons who 
have been convicted of crimes and are incarcerated. The enforcement task forces target aliens at 
different points in the criminal justice process, with the NFOP focusing on at-large convicted 
criminal aliens (including those who have served jail time and then been released) and fugitive 
aliens, who may not have been convicted of criminal offenses, and §287(g) task forces focusing 
on a range of different types of suspected criminals. 
DHS Enforcement Priorities and Discretion 
Not all potentially removable aliens who come into contact with DHS and other law enforcement 
agencies are placed in formal removal procedures. DHS estimates that there were about 11.5 
million unauthorized immigrants in the United States in January 2011,69 and DHS apprehended an 
average of 827,000 removable aliens per year from FY2008 to FY2011.70 These apprehension 
numbers do not include additional removable aliens who are transferred to ICE after being 
apprehended by other federal, state, and local law enforcement agencies. Yet ICE and its partner 
agencies only have the detention bed space and institutional capacity to remove about 400,000 
aliens per year.71 
Thus, DHS—like the INS before it—has developed a system to prioritize certain aliens for 
removal.72 Accordingly, ICE has published a number of agency guidance memos concerning the 
agency’s enforcement priorities and prosecutorial discretion, including in March and June of 
2011. In August 2011, DHS Secretary Janet Napolitano announced that the recent memos apply to 
all DHS enforcement agencies. DHS also announced, in June 2012, that the department would 
exercise prosecutorial discretion by deferring enforcement action in the case of certain individuals 
who were brought to the United States as children and who meet certain other criteria. 
                                                 
69 Michael Hoefer, Nancy Rytina, and Bryan C. Baker, Estimates of the Unauthorized Immigrant Population Residing 
in the United States: January 2011, Office of Immigration Statistics, Department of Homeland Security, 2012. 
70 DHS apprehensions include U.S. Border Patrol apprehensions and ICE administrative arrests; see Department of 
Homeland Security Office of Immigration Statistics, Yearbook of Immigration Statistics: 2011, Washington, DC 2012.  
71 John Morton, Memorandum on Civil Immigration Enforcement: Priorities for the Apprehension, Detention, and 
Removal of Aliens, US Immigration and Customs Enforcement, Washington, DC, March 2, 2011, http://www.ice.gov/
doclib/news/releases/2011/110302washingtondc.pdf. 
72 Ibid. On INS policies related to prosecutorial discretion and the prioritization of certain aliens for removal see INS 
General Counsel Bo Cooper, INS Exercise of Prosecutorial Discretion, U.S. INS, Washington, DC, July 11, 2000; INS 
Commissioner Doris Meissner, Exercising Prosecutorial Discretion, U.S. INS, Washington, DC, November 17, 2000; 
and INS General Counsel Bo Cooper, Motions to Reopen for Considerations of Adjustment of Status, U.S. INS, 
Washington, DC, May 17, 2001. 
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March 2011 ICE Guidance Memo 
In March 2011, ICE Director John Morton published agency guidelines that define a three-tiered 
priority scheme that applies to all ICE programs and enforcement activities related to civil 
immigration enforcement.73 Under these guidelines, ICE’s top three immigration enforcement 
priorities are to (1) apprehend and remove aliens who pose a danger to national security or a risk 
to public safety, (2) apprehend and remove recent illegal entrants,74 and (3) apprehend aliens who 
are fugitives or otherwise obstruct immigration controls.  
The 2011 guidelines further describe aliens within the first priority category to include aliens who 
have engaged in or are suspected of terrorism or espionage; aliens convicted of crimes (i.e., 
criminal aliens), especially violent criminals, felons, and repeat offenders; gang members; aliens 
subject to outstanding criminal warrants; and aliens who otherwise pose a risk to public safety. 
Thus, while the memo places all criminal aliens within its top enforcement priority category, it 
also describes an additional three-tiered system for prioritizing the removal of criminal aliens, 
with special attention directed to Level 1 and Level 2 offenders:  
•  Level 1 offenders: aliens convicted of “aggravated felonies,” as defined in 
§101(a)(43) of the Immigration and Nationality Act, or of two or more crimes 
each punishable by more than one year (i.e., two or more felonies); 
•  Level 2 offenders: aliens convicted of any felony or three or more crimes each 
punishable by less than one year (i.e., three or more misdemeanors); 
•  Level 3 offenders: aliens convicted of two or fewer misdemeanors. 
The memo specifies that aliens are categorized based on their lifetime criminal records. For 
example, an alien previously convicted of an aggravated felony is considered a Level 1 offender 
even if they were most recently arrested for a traffic violation. 
June 2011 ICE Guidance Memo 
ICE Director John Morton published an additional memo in June 2011 to provide further 
guidance to ICE officers, agents, and attorneys to target criminal aliens for enforcement.75 The 
                                                 
73 ICE’s mission includes the criminal and civil enforcement of federal laws governing border control, customs, trade, 
and immigration; see ICE, “ICE Overview: Mission,” http://www.ice.gov/about/overview/. Laws governing the 
detention and removal of unauthorized aliens generally fall under ICE’s civil enforcement authority, while laws 
governing the prosecution of crimes, including immigration-related crimes, fall under ICE’s criminal enforcement 
authority. Also see Hiroshi Motomura, “The Discretion That Matters: Federal Immigration Enforcement, State and 
Local Arrests, and the Civil-Criminal Line,” UCLA Law Review, vol. 58, no. 6 (August 2011), pp. 1819-1858. 
74 The memo does not define “recent illegal entrants,” but ICE Deputy Director Kumar Kibble testified on October 4, 
2011 that ICE defines the term “in terms of years, not months.” U.S. Congress, House Committee on Homeland 
Security, Subcommittee on Border and Maritime Security, Does Administrative Amnesty Harm our Efforts to Gain and 
Maintain Operational Control of the Border, 112th Cong., 1st sess., October 4, 2011, Q & A session. DHS regulations 
permit immigration officers to summarily exclude an alien present in the United States for less than two years unless 
the alien expresses an intent to apply for asylum or has a fear of persecution or torture; see CRS Report RL33109, 
Immigration Policy on Expedited Removal of Aliens, by Alison Siskin and Ruth Ellen Wasem. 
75  John Morton, Exercising Prosecutorial Discretion Consistent with the Civil Immigration Enforcement Priorities of 
the Agency for the Apprehension, Detention, and Removal of Aliens, U.S. Department of Homeland Security 
Immigration and Customs Enforcement, Washington, DC, June 17, 2011, http://www.ice.gov/doclib/secure-
communities/pdf/prosecutorial-discretion-memo.pdf. A separate memo published at the same time advises ICE officers, 
(continued...) 
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memo clarifies that because ICE “is confronted with more administrative violations than its 
resources can address, the agency must regularly exercise ‘prosecutorial discretion’ … to 
prioritize its efforts.”76 It states that any law enforcement agency may exercise prosecutorial 
discretion in the ordinary course of enforcement by deciding “not to assert the full scope of the 
enforcement authority available to the agency in a given case.” In ICE’s case, prosecutorial 
discretion may include, among other actions, deciding not to issue or to cancel a detainer; 
deciding not to issue a Notice to Appear (initiating removal proceedings); deciding to release an 
alien on bond; permitting an alien to voluntarily depart the country instead of placing the alien in 
formal removal proceedings; granting deferred action, parole, or a stay of a final removal order; 
and joining a motion to grant relief from removal. The memo further clarifies that ICE 
Enforcement and Removal Operations officers, special agents, and attorneys each may exercise 
discretion in any immigration removal proceeding.77 Finally, the memo identifies a list of at least 
19 factors to consider when exercising prosecutorial discretion, including eight factors that should 
mitigate in favor of exercising discretion and four factors that should mitigate against exercising 
discretion.78 
August 2011 DHS Announcement and Review of Backlogged Cases 
On August 18, 2011, DHS Secretary Janet Napolitano announced in a letter to Senator Richard 
Durbin and others that the March and June ICE guidance memos were Administration policy, and 
that the same guidance would apply to all DHS immigration agencies.79 The letter also indicated 
DOJ resources should be targeted toward high-priority cases.80 The White House issued a 
                                                                  
(...continued) 
special agents, and attorneys to particularly consider prosecutorial discretion for victims of domestic violence, human 
trafficking or other serious crimes; witnesses involved in pending criminal investigations or prosecutions; plaintiffs in 
non-frivolous lawsuits regarding civil rights or liberties violations; and individuals engaging in a protected activity 
related to civil or other rights. See John Morton, Prosecutorial Discretion: Certain Victims, Witnesses, and Plaintiffs, 
U.S. Department of Homeland Security Immigration and Customs Enforcement, Washington, DC, June 17, 2011, 
http://www.ice.gov/doclib/secure-communities/pdf/domestic-violence.pdf. 
76 Morton, Exercising Prosecutorial Discretion, p. 2. 
77 Ibid, pp. 2-3. 
78 The eight factors mitigating in favor of discretion include humanitarian factors and factors related to aliens’ 
attachment to their communities in the United States, including whether aliens are veterans or members of the armed 
forces; whether they are long-time lawful permanent residents; whether they are minors or elderly; whether they have 
been in the United States since childhood; whether they are pregnant or nursing; whether they are victims of domestic 
violence, trafficking, or other serious crimes; whether they suffer from a serious disability; and whether they have a 
serious health condition. The four factors mitigating against discretion include public safety and security concerns, 
including whether aliens pose a clear risk to national security; whether they are serious felons, repeat offenders, or 
individuals with lengthy criminal records of any kind; whether they are known gang members or otherwise pose a clear 
danger to public safety; and whether they have an egregious record of immigration violations. Other factors identified 
in the memo include the agency’s civil immigration priorities; whether the alien is pursuing an education in the United 
States; whether the alien has ties to the community; whether the alien has ties to the home country and the conditions 
there; whether the alien is a primary caretaker of a person with a mental or physical disability; whether the alien’s 
nationality renders removal unlikely; whether the person is likely to be granted relief from removal; and whether the 
alien is cooperating or has cooperated with federal, state, or local enforcement authorities. Ibid, pp. 4-5. 
79  Letter from Janet Napolitano, Secretary of Homeland Security, to Richard Durbin, Senator, August 18, 2011; also 
see Robert Pear, “Few Youths to be Deported in New Policy,” The New York Times, August 18, 2011, p. A1, 
http://www.nytimes.com/2011/08/19/us/19immig.html?_r=2&hp.; U.S. Congress, Senate Committee on the Judiciary, 
Oversight of the Department of Homeland Security, testimony of DHS Secretary Janet Napolitano, 112th Cong., 1st 
sess., October 19, 2011. 
80 Ibid.; immigration judges also have some leeway to grant certain forms of relief during the removal process, 
(continued...) 
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statement the same day to further clarify that DHS’s enforcement priorities were a matter of 
Administration policy, developed “under the president’s direction.”81 
At the same time, the White House and DHS announced that DHS and DOJ would begin to 
review removal cases that were awaiting hearings in immigration courts.82 Under the program, an 
inter-agency group of DHS and DOJ attorneys has reviewed backlogged cases to identify low-
priority cases that may be amenable to prosecutorial discretion, with the goal of pulling such 
cases out of the immigration court docket in order to focus judicial and prosecution resources on 
higher-priority cases. As of May 29, 2012, the program had reviewed a total of 288,361 of the 
approximately 300,000 backlogged cases. Of the cases reviewed, about 20,648 (7.2%) were 
identified as potentially amendable to prosecutorial discretion, and 4,363 (1.9%) had been 
administratively closed or dismissed, and the remaining cases remain on the immigration court 
docket.83 
Deferred Action for Childhood Arrivals (DACA) 
On June 15, 2012, DHS issued a memorandum announcing that certain individuals who were 
brought to the United States as children and meet other criteria would be considered for deferred 
action for two years, subject to renewal.84 Deferred action is a “discretionary determination to 
defer removal action of an individual as an act of prosecutorial discretion.”85 The Deferred Action 
for Childhood Arrivals (DACA) program builds on the ICE and DHS initiatives discussed above 
in that it is based on a grant of prosecutorial discretion,86 but it also relates to a broader policy 
debate about legalization for certain unauthorized migrants because the eligibility criteria 
described in the DACA program are similar to those that would grant legal status to certain aliens 
under legislation known as the “DREAM Act.”87 According to DHS, the DACA program 
promotes the department’s enforcement priorities because granting deferred action to low-priority 
cases frees up law resources to focus enforcement on higher priority cases.88 Some Members of 
                                                                  
(...continued) 
including through the granting of voluntary departure as an alternative to formal removal. 
81 White House Director of Intergovernmental Affairs Cecilia Muñoz, “Immigration Update: Maximizing Public Safety 
and Better Focusing Resources,” August 18, 2011, http://www.whitehouse.gov/blog/2011/08/18/immigration-update-
maximizing-public-safety-and-better-focusing-resources. 
82 Ibid.; also see Letter from Janet Napolitano, Secretary of Homeland Security, to Richard Durbin, Senator, August 18, 
2011. 
83 ICE, “Case by Case Review Statistics,” http://www.documentcloud.org/documents/367098-ice-review-stats.html; 
also see Julia Preston, “Deportations Continue Despite U.S. Review of Backlog, The New York Times, June 6, 2012. 
84 DHS, “Deferred Action for Childhood Arrivals,” June 15, 2012, http://www.dhs.gov/deferred-action-childhood-
arrivals. Also see CRS Congressional Distribution Memorandum, Analysis of June 15, 2012 DHS Memorandum, 
“Exercising Prosecutorial Discretion with Respect to Individuals Who Came to the United States as Children,” by 
Andorra Bruno, Todd Garvey, Kate Manuel, and Ruth Ellen Wasem (available from the authors).  
85 Ibid. 
86 According to DHS, the exercise of prosecutorial discretion for certain aliens who meet DREAM Act criteria was 
undertaken as part of the Administration’s “unprecedented effort to transform the immigration enforcement system into 
on that focuses on public safety, border security and the integrity of the immigration system…. [by ensuring] that 
enforcement resources are not expended on low priority cases”; DHS, “Deferred Action for Childhood Arrivals,” June 
15, 2012, http://www.dhs.gov/deferred-action-childhood-arrivals. 
87 See CRS Report RL33863, Unauthorized Alien Students: Issues and “DREAM Act” Legislation, by Andorra Bruno. 
88 See, for example, DHS, “Secretary Napolitano Announced Deferred Action Process for Young People Who Are Low 
Enforcement Priorities,” June 15, 2012, http://www.dhs.gov/news/2012/06/15/secretary-napolitano-announces-
(continued...) 
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Congress have expressed frustration about the deferred action announcement and questioned its 
legality,89 while others have expressed support for the program.90 As of December 2012, DHS had 
received a total of 367,903 applications to participate in the deferred action program; 12,014 (3%) 
of the applications had been rejected; 102,965 (28%) had been approved; and the remainder 
remained under review or were being scheduled for review.91 
Appropriations  
Funding for the identification and removal of unauthorized immigrants has increased 
substantially since FY2004, the first year in which DHS received dedicated funding for detention 
and removal operations. Table 5 presents funding figures for overall ICE DRO/ERO operations 
and for the CAP, Secure Communities, NFOP, and §287(g) programs. DRO/ERO is ICE’s largest 
Salaries and Expenses subaccount; CAP, NFOP, and Secure Communities (“Identification and 
removal of criminal aliens”) are funded program activities within DRO/ERO; and §287(g) is 
funded under ICE’s Office of State, Local, and Tribal Government Coordination.  
The appropriations record confirms Congress’s ongoing interest in strengthening these programs. 
Congress roughly tripled funding for CAP and NFOP in FY2005 and FY2006 over the previous 
years, and appropriators directed ICE to conduct a study of how the Institutional Removal 
Program could be expanded nationwide.92 In 2008, appropriators expressed concern that ICE was 
“losing perspective on which aliens represent the most significant threat to the nation’s social and 
economic fabric” and questioned “why a significant number of illegal aliens serving sentences in 
State and local correctional facilities after conviction for various non-immigration crimes are still 
released from custody without efforts made to deport those who are deportable.”93 
                                                                  
(...continued) 
deferred-action-process-young-people-who-are-low. 
89 See, for example, Letter from Senator Charles Grassley, et al., to Barack Obama, President, June 19, 2012. 
90 See, for example, Letter from the Honorable Luis V. Gutierrez, Representative, et al., to Barack Obama, President, 
July 19, 2012. For a discussion of the legal issues surrounding prosecutorial discretion in the context of immigration 
enforcement, see CRS Legal Sidebar, “How Broad is the Executive Branch’s Discretion to Enforce Immigration 
Laws?” June 21, 2012, http://www.crs.gov/analysis/legalsidebar/pages/details.aspx?ProdId=85. 
91 U.S. Citizenship and Immigration Services, “Deferred Action for Childhood Arrivals Process,” December 13, 2012, 
http://www.uscis.gov/USCIS/Resources/Reports%20and%20Studies/Immigration%20Forms%20Data/
All%20Form%20Types/DACA/DACA%20MonthlyDEC%20Report%20PDF.pdf.pdf. 
92  U.S. Congress, Senate Committee on Appropriations, Subcommittee on Department of Homeland Security, 
Department of Homeland Security Appropriations Bill, 2006, Report to accompany H.H. 2360, 109th Cong., 1st sess., 
June 16, 2005, 109-83 (Washington: GPO, 2005), p. 36. 
93  U.S. Congress, House Committee on Appropriations, Department of Homeland Security Appropriations Bill, 2008 
H.Rept. 110-181, 110th Cong., 2008 (Washington: GPO, 2008). 
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Table 5. Appropriations for Programs Targeting Criminal Aliens, FY2004-FY2011 
(millions of dollars) 
 
Total: 
Criminal 
All Other 
Total 
Fiscal 
Secure 
Aliens 
DRO/ERO 
DRO/ERO 
Year CAPc 
Communitiese §287(g)d NFOP Programsb  Operations  Operationsa 
2004 
$6.6 NAg NAf $16.9  $23.4 $936.3 $959.7 
2005 
$33.7 NA 
NA $35.2 $69.0 $1,022.2 $1,091.1 
2006 
$93.0 NA 
$5.0 
$101.9 
$199.9 $1,160.1 $1,359.9 
2007 
$137.5 NA  $15.0 
$183.2 
$335.7 $1,648.7 $1,984.3 
2008 
$180.0 $200.0  $42.1 
$218.9 $641.1 $1,740.3 $2,381.4 
2009 
$189.1 $150.0  $54.0 
$226.5 $619.5 $1,861.7 $2,481.2 
2010 
$192.5 $200.0  $68.0 
$229.7 $690.2 $1,855.0 $2,545.2 
2011 
$192.5 $200.0  $68.0 
$229.7 $690.2 $1,855.0 $2,545.2 
2012 
$196.7 $189.1  $68.0 
$154.6 $608.4 
$2,142.4 
$2,750.8 
2013 
$216.7 $138.7  $51.0 
$132.9 $539.3 
$2,139.5 
$2,678.8 
Total  $1,438.3 $1,077.8  $371.1 
$1,5295 $4,416.7 $16,361.2 $20,777.6 
Sources: DRO, CAP, Secure Communities, and NFOP data from S.Rept. 108-280, S.Rept. 109-83, S.Rept. 109-
273, H.Rept. 109-699, S.Rept. 110-396, S.Rept. 111-31, S.Rept. 111-222, and S.Rept. 112-169; §287(g) data from 
U.S. Immigration and Customs Enforcement “Fact Sheet: Updated Facts on ICE’s 287(g) Program” and from 
S.Rept. 111-222. 
Notes: FY2013 data are requested amounts. CAP refers to the Criminal Alien Program; NFOP refers to the 
National Fugitive Operations Program; 287(g) refers to agreements entered pursuant to INA §287(g) for jailing 
screening or task force programs; LEA refers to law enforcement agent; ICE refers to the U.S. Immigration and 
Customs Enforcement agency; DRO/ERO refers to Detention and Removal Operations/Enforcement and 
Removal Operations. 
a.  Detention and Removal Operations was renamed Enforcement and Removal Operations in 2010.  
b.  Includes funding for CAP, Secure Communities, the §287(g) program, and NFOP.  
c.  The Criminal Alien Program was known as the Institutional Review Program prior to FY2007.  
d.  Includes §287(g) jail enforcement and §287(g) task force programs.  
e.  Secure Communities was known as the Comprehensive Identification and Removal of Criminal Aliens 
program in FY2008.  
f. 
The §287(g) program received its first appropriation in FY2006.  
g.  The Secure Communities program received its first appropriation in FY2008.  
Accordingly, appropriators increased funding for the existing Criminal Alien Program in FY2008; 
and set aside $200 million in additional funding for the Comprehensive Identification and 
Removal of Criminal Aliens, a program to “improve and modernize efforts to identify aliens 
convicted of a crime, sentenced to imprisonment, and who may be deportable, and remove them 
from the United States once they are judged deportable.”94 ICE used the additional funding to 
support CAP and to develop Secure Communities.  
                                                 
94  U.S. Congress, House Committee on Rules, Providing for the consideration of the Senate amendment to the bill 
(H.R. 2764) making appropriations for the Department of State, foreign operations, and related programs for the fiscal 
(continued...) 
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Funding dedicated specifically to the identification and removal of criminal aliens (i.e., funding 
for CAP and Secure Communities) increased from just $6.6 million in FY2004 to $385.8 million 
in FY2012, a 57-fold increase. This figure understates appropriations targeting criminal aliens 
since it does not include funding for NFOP and the §287(g) program, both of which also include 
criminal aliens in their enforcement mandates. Altogether, the four programs targeting criminal 
aliens saw their funding grow from $23.4 million in FY2004 to a high of $690.2 million in 
FY2011 before declining to $539.3 million (requested) in FY2013. Funding for DRO/ERO 
operations overall—all of which treat removable criminal aliens as an enforcement priority—
increased from $960 million in FY2004 to a high of $2.75 billion in FY2012. More than $20 
billion was appropriated to alien removal programs between FY2004 and FY2013. 
Enforcement Statistics  
Enforcement data can be an indicator of the degree to which appropriations for interior 
enforcement have translated into enforcement actions. Table 6 presents data on primary 
enforcement actions by the four enforcement programs discussed in this report from 2004 through 
2011. The table presents data on administrative arrests95 by CAP, §287(g), and NFOP, and on 
alien identifications as well as returns and removals resulting from Secure Communities. (The 
four programs do not produce directly comparable enforcement statistics because Secure 
Communities is only responsible for the identification of removable aliens, while the other 
programs also encompass measures to arrest removable aliens.)  
Table 6. Primary Interior Enforcement Actions, by Program, FY2004-FY2011 
CAP 
Secure Communities 
§287(g)  
NFOP 
Fiscal 
Removals 
Arrests  
Year 
Arrests Identifications 
and Returns 
Arrests 
2004 4,269 
NA 
NA 
0  6,584 
2005 25,339 
NA 
NA 
2 
7,959 
2006 28,493 
NA 
NA  5,685  15,462 
2007 164,296 
NA 
NA  20,815 
30,407 
2008 221,085 
NA 
NA  45,105 
34,155 
2009 232,796 
95,664 
14,364  56,116 
35,094 
2010 219,477  248,166 
45,907  46,467 
35,774 
2011 221,122  348,970 
79,896  33,180 
39,466 
Total 1,116,877 
692,800 
140,167 
207,370 
204,901 
Source: CAP, §287(g), and NFOP data received from ICE Legislative Affairs October 12, 2011, except for 
FY2011 CAP data, which are from ICE Congressional Budget Justification, FY2013; Secure Communities data are 
from Secure Communities IDENT/IAFIS Interoperabilty Monthly Statistics through August 31, 2012. 
                                                                  
(...continued) 
year ending September 30, 2008, and for other purposes, 110th Cong., December 17, 2007. 
95 An administrative arrest refers to the arrest of an alien who is charged with an immigration violation and typically 
placed in removal proceedings.  
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Notes: CAP refers to the Criminal Alien Program; NFOP refers to the National Fugitive Operations Program; 
287(g) refers to agreements entered pursuant to INA §287(g) for jailing screening or task force programs. The 
same cases may be counted multiple times in Table 6. CAP data are for the Institutional Removal Program in 
FY2004-FY2006. Data are unavailable for Secure Communities for FY2004-FY2008 because the program was 
created in FY2008 and reported its first identifications and removals in FY2009. ICE reported Secure 
Communities administrative arrests in its quarterly reports to Congress through April 2011 but since August 
2011 ICE has reported on combined removals and returns through the program rather than administrative 
arrests. Data for the §287(g) program and NFOP are through October 1, 2011. 
Data in Table 6 should be interpreted with caution, particularly when it comes to Secure 
Communities, for two reasons. First, while Secure Communities is directly responsible for the 
identification of potentially removable aliens, the program does not make arrests or place aliens 
in removal proceedings. Rather, when an ICE field office determines through Secure 
Communities that an alien should be placed in removal proceedings, the arrest and subsequent 
enforcement proceedings occur outside of Secure Communities per se, usually by an ICE officer 
from CAP or a §287(g) program.  
Second, for this reason, Table 6 includes a number of over-counts (i.e., the same case appearing 
in multiple columns in the table) because the same individual is counted as an identification, 
removal, or arrest by multiple programs. The same individual may also be identified or arrested 
on multiple occasions, causing additional over-counts. In addition, some removable aliens are 
arrested or placed in removal proceedings outside of these four programs, so the data in Table 6 
should not be interpreted as an exhaustive accounting of ICE or DHS enforcement programs. 
With those qualifications, the data in Table 6 indicate consistent increases in the number of aliens 
identified and arrested by these four programs. Available data indicate that CAP made over 1.1 
million administrative arrests between FY2004 and FY2011, while the §287(g) program and 
NFOP made about 207,000 and 205,000 administrative arrests, respectively. 
Secure Communities has quickly grown to identify an even larger number of removable aliens per 
year than CAP, with just under 350,000 potentially removable aliens identified in FY2011. From 
FY2009 through the first nine months of FY2012, a total of about 19.9 million sets of biometric 
data were submitted to Secure Communities, resulting in the identification of about 1.1 million 
matches in the IDENT database (i.e., potentially removable aliens), and a total of 220,322 aliens 
removed or returned as a result of those identifications.96 Thus, about 5% of all submissions to 
Secure Communities are identified as potentially removable aliens, and about 20% of people so 
identified (i.e., about 1% of all submissions) had been removed or returned as of August 2012. 
Table 7 presents a rudimentary measure of each program’s cost per individual identified, 
removed and returned, or arrested. The figures were derived by dividing each program’s annual 
appropriations (Table 5) by the number of enforcement actions reported for the program in that 
year (Table 6). They indicate that as the number of arrests and identifications for the programs 
have increased, the cost per case has declined substantially and appears to have stabilized for 
some programs in the most recent years.  
These figures are illustrative and allow broad comparisons across programs, but do not reflect 
precise estimates of arrest costs given the over-counting of certain arrest data. Moreover, the 
programs share certain resources and administrative costs. For example, CAP officers oversee 
                                                 
96 Secure Communities IDENT/IAFIS Interoperabilty Monthly Statistics through August 31, 2012, p. 2. An unknown 
number of individuals may appear more than once in these data. 
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certain §287(g) programs and are responsible for the administrative arrest and removal of aliens 
identified through Secure Communities. In addition, funding differences reflect the different 
scope of enforcement activities under these programs. For example, the NFOP apprehends, 
arrests, and processes at-large removable aliens, while Secure Communities simply identifies 
them as they pass through the criminal justice system. With respect to the NFOP and certain 
§287(g) programs, the higher cost of conducting task force operations relative to jail enforcement 
may be warranted given their greater focus on high-priority cases and more extensive 
enforcement activities. 
Table 7. Ratio of Appropriations to Enforcement Actions, by Program, 
FY2004-FY2011 
CAP 
Secure Communities 
§287(g)  
NFOP 
Arrests  
Year 
Arrests Identifications Removals 
Arrests 
and Returns 
2004 $1,546 
NA 
NA 
NA  $2,567 
2005 $1,330 
NA 
NA 
NA  $4,423 
2006 $3,264 
NA 
NA 
$880  $6,590 
2007 $837 
NA 
NA  $721  $6,025 
2008 $814 
NA 
NA  $933  $6,409 
2009 $812  $1,568  $10,442  $962  $6,454 
2010 $877  $806  $4,357  $1,463  $6,421 
2011 $888  $573  $2,503  $2,049  $5,820 
Source: Figures are computed by dividing annual appropriations for the program shown in Table 5 by the 
number of identifications and arrests by program shown in Table 6.  
Notes: CAP refers to the Criminal Alien Program; NFOP refers to the National Fugitive Operations Program; 
287(g) refers to agreements entered pursuant to INA §287(g) for jailing screening or task force programs. CAP 
data are for the Institutional Removal Program in FY2004-FY2006. §287(g) data include jail enforcement and task 
force programs. Data are unavailable for Secure Communities for FY2004-FY2008 because the program was 
created in FY2008 and reported its first identifications and arrests in FY2009, and data are unavailable for §287(g) 
in FY2004-FY2005 because the program received its first appropriation in FY2006. Secure Communities is 
responsible for the identification of removal aliens, but the administrative arrest, removal, and return of aliens 
falls outside the scope of the program. Data for the §287(g) program and NFOP are based on enforcement 
statistics through October 1, 2011. 
Controversies Surrounding Interior 
Enforcement Programs  
While there appears to be a broad consensus that DHS should target serious criminal aliens for 
removal, ICE’s interior enforcement programs have been controversial, particularly the §287(g) 
program and Secure Communities. Complaints about the §287(g) program in 2007-2009 
prompted reviews of the program by GAO and the DHS Inspector General,97 and both agencies 
                                                 
97 U.S. Government Accountability Office, Immigration Enforcement: Better Controls Needed over Program 
Authorizing State and Local Enforcement of Federal Immigration Laws, GAO-09-109, January 2009, 
(continued...) 
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are currently examining Secure Communities. Opponents of Secure Communities called for its 
termination during field hearings held by a DHS task force in August 2011. A class action lawsuit 
was also filed in 2011 challenging the constitutionality of DHS’s use of immigration detainers 
against immigrants and U.S. citizens identified through Secure Communities.98 
This section describes the overall rationale behind ICE’s jail enforcement programs and its 
collaboration with state and local law enforcement agencies and then describes the concerns that 
have been raised about these programs as well as counter-arguments made by supporters of the 
programs. The section then discusses whether jurisdictions may choose not to participate in 
Secure Communities and changes to Secure Communities announced by ICE in June 2011. 
The Rationale Behind Secure Communities and the 
§287(g) Program  
DHS supported the expansion of the §287(g) program beginning in 2007, and since 2008 it has 
supported plans to expand Secure Communities to every law enforcement jurisdiction in the 
country by the end of 2013.99 Some Members of Congress, state and local lawmakers, and 
advocacy groups also support these programs and their expansion.100 
Jail enforcement programs like Secure Communities, CAP, and certain §287(g) agreements 
appear to enhance ICE’s ability to identify and detain criminal aliens; first, because partnerships 
with state and local law enforcement agencies can leverage ICE’s enforcement capacity, and 
second, because they can detect potentially removable aliens efficiently and quickly.  
Partnerships with State and Local Law Enforcement Agencies Augment ICE’s 
Enforcement Capacity 
Partnerships with state and local law enforcement agencies leverage ICE’s enforcement capacity 
because there are about 150 times more state and local law enforcement officers in the United 
States than there are ICE agents: 1,133,000 state and local law enforcement personnel, including 
765,000 sworn personnel with arrest powers, compared to 20,164 ICE agents, including 5,131 
employed in enforcement and removal operations.101 State, local, and federal law enforcement 
                                                                  
(...continued) 
http://www.gao.gov/new.items/d09109.pdf; Department of Homeland Security, Office of Inspector General, The 
performance of 287(g) Agreements, OIG-10-63, March 2010, http://www.dhs.gov/xoig/assets/mgmtrpts/OIG_10-
63_Mar10.pdf. 
98 See National Immigration Justice Center, “NIJC Sues Department of Homeland Security Over Key Component of 
Secure Communities Program,” http://immigrantjustice.org/press_releases/detainers-lawsuit. 
99 For the Administration’s views of Secure Communities see U.S. Immigration and Customs Enforcement, Secure 
Communities, March 2011, http://www.ice.gov/secure_communities/. Also See, for example, Maria Sacchetti, “U.S. 
Set to Expand Deportation Program,” Boston Globe, August 6, 2011. 
100 See, for example, U.S. Congress, Senate Committee on the Judiciary, Subcommittee on Immigration, Refugees and 
Border Security, Improving Security and Facilitating Commerce at America’s Northern Border and Ports of Entry, 
112th Cong., 1st Sess., May 17, 2011, pp. 59-60; Jessica M. Vaughan and James R. Edwards, The 287(g) Program: 
Protecting Hometowns and the Homeland, Center for Immigration Studies, Washington, DC, October 2009, 
http://www.cis.org/articles/2009/287g.pdf. 
101 State and local law enforcement data are for full time employees in 2008 according to Brian A. Reaves, Census of 
State and Local Law Enforcement Agencies, 2008, U.S. Department of Justice Bureau of Justice Statistics, NCJ 
(continued...) 
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officials made a total of 12,408,899 arrests (citizens and noncitizens) in 2011 compared to a total 
of about 55,762 arrests by ICE.102 
Thus, even though most state and local arrests are of U.S. citizens for cases unrelated to 
immigration enforcement, any policies that forge connections between state and local law 
enforcement agents and ICE have the potential to increase ICE’s presence in U.S. communities 
and may be substantial force multipliers for ICE. State and local law enforcement agents may also 
have stronger connections to local communities, further enhancing their ability to contribute to 
ICE’s enforcement efforts. 
Jail Enforcement Programs Are Efficient Tools to Identify Criminal Aliens and 
Other Potentially Removable Aliens 
Jail enforcement programs like Secure Communities, CAP, and certain §287(g) programs conduct 
immigration-related screening at natural “choke points” in the criminal justice system, including, 
in particular, during the booking process. As noted above, when people are booked into jail after 
being arrested, corrections facilities typically create a biographic and biometric record of the 
arrestee, including the person’s name, other identifying information, fingerprints, and 
photographs. By using these same data to check for possible immigration violations while 
individuals are already in law enforcement custody, jail enforcement programs can efficiently 
identify potentially removable aliens as they pass through the criminal justice system.  
Jail Enforcement Programs Identify Potentially Removable Aliens Early in the 
Criminal Justice Process 
By conducting immigration-related screening as people are being booked into jail, Secure 
Communities and certain CAP and §287(g) programs may identify potentially removable aliens 
early in the criminal justice process, giving ICE an opportunity to request an immigration detainer 
and initiate removal proceedings against certain aliens who might otherwise be released back into 
the community. Screening later in the criminal justice process, as in CAP’s screening of prisoners 
who have already been convicted of crimes, also detects certain criminal aliens who are convicted 
and sentenced to prison; but if screening is limited to such aliens, jail enforcement programs may 
fail to detect certain removable aliens who are not convicted of crimes but still fall under one of 
ICE’s enforcement priorities (e.g., because they have previous serious criminal convictions or are 
recent illegal entrants). 
                                                                  
(...continued) 
233982, Washington, DC, July 2011, http://bjs.ojp.usdoj.gov/content/pub/pdf/csllea08.pdf. ICE data are for full time 
employees in FY2011 according to U.S. Department of Homeland Security, U.S. Immigration and Customs 
Enforcement Fiscal Year 2011 Congressional Justification. 
102 Total arrest data are from U.S. Department of Justice Federal Bureau of Investigation, “Crime in the United States: 
Persons Arrested. 2011,” http://www.fbi.gov/about-us/cjiys/ucr/crime-in-the-u.s/2011/crime-in-the-u.s.-2011/persons-
arrested/persons-arrested; ICE arrest data are CRS estimate based on FY2011 NFOP arrest data in Table 6 and ICE 
Homeland Security Investigations apprehension data from Department of Homeland Security Office of Immigration 
Statistics, “Immigration Enforcement Actions: 2011,” http://www.dhs.gov/sites/default/files/publications/immigration-
statistics/enforcement_ar_2011.pdf. 
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Additional Potential Advantages of Particular Jail Enforcement Programs  
Each ICE jail enforcement program offers additional potential advantages: 
•  Secure Communities is an especially efficient tool to identify removable aliens 
because it exploits existing infrastructure to conduct immigration screening on an 
automated basis, relying on interoperability between DHS and DOJ databases. 
Following the identification of a potential match, additional data matching and 
prioritization occurs at a centralized ICE location, the Law Enforcement Support 
Center (LESC), creating economies of scale in the screening process. Thus, 
compared with CAP and the §287(g) program, Secure Communities may identify 
removable aliens with minimal additional personnel or infrastructure. 
•  Secure Community’s use of biometric matching technology allows records to be 
checked quickly against a large number of DHS records, including over 148 
million records in the U.S. Visitor and Immigrant Status Indicator Technology 
(US-VISIT) Automated Biometric Identification System (IDENT) database.103 
According to ICE, Secure Communities conducts electronic checks against DHS 
databases within minutes of fingerprint data from a person’s booking being sent 
to the FBI. The LESC usually reviews any electronic matches and notifies an ICE 
field office within four hours from when a potentially removable alien has been 
identified.104 
•  Secure Communities gives ICE greater control over enforcement. Conversely, the 
§287(g) program has faced criticism because in delegating authority to state and 
local law enforcement agents, it may give these offices undue discretion to shape 
immigration enforcement decisions, resulting in different standards for 
immigration enforcement across jurisdictions.105 Under Secure Communities, 
DHS officers make enforcement decisions with respect to aliens identified 
through the program. Thus, Secure Communities may avoid some concerns that 
have been raised about the §287(g) program, and may give DHS greater control 
over how jail enforcement programs are implemented. 
•  The CAP and §287(g) programs may be more powerful (though less efficient) 
enforcement tools than Secure Communities because they place additional 
immigration enforcement agents in state and local jurisdictions: either ICE agents 
under CAP, or ICE-trained state or local agents under the §287(g) program. In 
general, CAP and §287(g) officers have access to the same databases that are 
checked by Secure Communities. CAP and §287(g) agents in the field or 
                                                 
103 US-VISIT communication with CRS December 11, 2012. The U.S. Visitor and Immigrant Status Indicator 
Technology (US-VISIT) system is a stand-alone division within DHS’s National Protection and Programs Directorate 
which is responsible for the collection of biometric data, including digital photographs and fingerprints, from certain 
travelers entering the United States and from individuals apprehended at U.S. borders. Biometric data are stored in the 
Automated Biometric Identification System (IDENT) database. See CRS Report RL32234, U.S. Visitor and Immigrant 
Status Indicator Technology (US-VISIT) Program, by Lisa M. Seghetti and Stephen R. Vina. 
104 ICE communication with CRS August 17, 2011. 
105 See, for example, U.S. Government Accountability Office, Immigration Enforcement: Better Controls Needed over 
Program Authorizing State and Local Enforcement of Federal Immigration Laws, GAO-09-109, January 2009, 
http://www.gao.gov/new.items/d09109.pdf; Randy Capps, Marc R. Rosenblum, and Cristina Rodríguez, et al., 
Delegation and Divergence: A Study of 287(g) State and Local Immigration Enforcement, Migration Policy Institute, 
Washington, DC, January 2011, http://www.migrationpolicy.org/pubs/287g-divergence.pdf. 
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connected via teleconference may also identify certain removable aliens who 
would not be detected through Secure Communities’ automated screening, 
including unauthorized aliens who enter without inspection and therefore are not 
in the IDENT database.  
•  While Secure Communities offers the advantage of centralized control, the 
§287(g) program offers the converse advantage of greater local control by 
allowing jurisdictions to devote additional resources to immigration enforcement 
as they deem necessary. (Local jurisdictions are not required to use any resources 
of their own to participate in Secure Communities, though they may expend 
resources to detain aliens identified through the program.) Similarly, while some 
lawmakers and advocates may question whether state and local jurisdictions are 
required to participate in Secure Communities, the structure of the §287(g) 
program unambiguously gives states and localities discretion to opt out or 
to participate. 
Concerns About Secure Communities and Other ICE Programs  
Despite the advantages of Secure Communities and the §287(g) program, several stakeholders 
have raised concerns about these programs. Some Members of Congress have called on 
jurisdictions to suspend their participation in the Secure Communities and have questioned ICE’s 
characterization of the program.106 The governors of Illinois, New York, and Massachusetts have 
taken steps to rescind their states’ participation in the program,107 though their ability to do so is 
unclear (see below). And numerous pro-immigrant, law enforcement, and civil liberties 
organizations have criticized the program and/or called for its modification, suspension, or 
termination.108 Many of the criticisms of Secure Communities echo concerns raised previously 
about the §287(g) program and the NFOP.109 
Four main concerns have been raised by critics of Secure Communities and other ICE programs 
targeting criminal aliens: first, the programs are not narrowly focused on serious criminals; 
second, the programs may strain community-police relations; third, the programs may 
inadvertently lead to racial profiling; and fourth, the programs may result in the wrongful 
                                                 
106 See, for example, Letter from Xavier Becerra, Member of Congress, Linda Sánchez, Member of Congress, Maxine 
Waters, Member of Congress, et al. to The Honorable Jerry Brown, Governor of the State of California, June 10, 2011, 
http://becerra.house.gov/images/stories/PDF_Forms/Ltr_to_Gov_Brown_re_Secure_Communities__06-10-
2011_final.pdf; “Congresswoman Calls for Investigation of Enforcement Program that Screens for Illegal Immigrants 
in Jails,” Los Angeles Times, April 22, 2011, http://latimesblogs.latimes.com/lanow/2011/04/congresswoman-calls-for-
investigation-of-enforcement-program-that-screens-for-illegal-immigrants-in-.html. 
107 Letter from Pat Quinn, Governor of Illinois, to Marc Rapp, Acting Assistant Director, Secure Communities, May 4, 
2011; letter from Deval Patrick, Governor of Massachusetts, to Marc Rapp, Acting Assistant Director, Secure 
Communities, June 3, 2011; letter from Andrew M. Cuomo, Governor of New York, to John Sandweg, Counselor to 
the Secretary, U.S. Department of Homeland Security, June 1, 2011, http://www.governor.ny.gov/assets/
Secure%20Communities.pdf. 
108 See, for example, National Community Advisory Commission, Restoring Community: A National Community 
Advisory Report on ICE’s Failed “Secure Communities Program, Washington, DC, August 2011, 
http://altopolimigra.com/documents/FINAL-Shadow-Report-regular-print.pdf. 
109 See, for example, American Civil Liberties Foundation of Georgia, “Brown Is Not a Crime: Stop 287(g) Racial 
Profiling,” http://www.acluga.org/287gReport.pdf; Margot Mendelson, Shayna Strom, and Michael Wishnie, 
“Collateral Damage: An Examination of ICE’s Fugitive Operations Program,” Migration Policy Institute, February 
2009, http://www.migrationpolicy.org/pubs/NFOP_Feb09.pdf. 
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detention of people who have not been convicted of a criminal offense. Supporters of these 
programs have offered counter-arguments to many of these concerns, and ICE announced 
changes to Secure Communities in June 2011 designed to address some of them (see “ICE Has 
Taken Steps to Address Concerns About Secure Communities and the §287(g) Program,” below). 
Jail Enforcement Programs Are Not Narrowly Focused on Serious Criminals 
A number of observers have raised concerns that ICE’s enforcement programs, which ostensibly 
focus on identifying and prosecuting the most dangerous criminal aliens, are detaining large 
numbers of noncriminal aliens whose only offense is having unauthorized status. Table 8 
illustrates the proportions of arrests from the §287(g) program and removals and returns from 
Secure Communities corresponding to four criminality levels: the three ICE levels described 
above (see “DHS Enforcement Priorities and Discretion”), and noncriminal offenses.110 For the 
§287(g) program, as the number of arrests increased between FY2006 and FY2011, the 
proportions of arrests involving Level 1 criminal aliens declined, while those for noncriminal 
arrests increased. Noncriminal offenses accounted for a plurality of §287(g) arrests each year 
except 2006. For Secure Communities, slightly more than a quarter of aliens removed and 
returned as a result of the program have been Level 1 criminal aliens, including 30% in the first 
nine months of FY2012. Slightly over half of the aliens removed and returned as a result of 
Secure Communities have been Level 3 criminals or noncriminals, with the proportions in these 
categories falling during each year for which data are available.  
Table 8. Removals and Returns Under Secure Communities and Arrests through the 
§287(g) Program, by Type of Offense, FY2006-FY2012 
(percentages) 
 
Secure Communities 
§287(g) Program 
 
Non-
Non-
Total 
Level 1  Level 2  Level 3  criminal 
Total 
Level 1  Level 2  Level 3  criminal 
2006 
NA 
NA NA NA  NA  100 
41 9 13 37 
2007 
NA 
NA NA NA  NA  100 
30 8 14 49 
2008 
NA 
NA NA NA  NA  100 
25 7 11 57 
2009 
100 
24 11 40  26 100 
22 8 16 54 
2010 
100 
29 13 32  27 100 23  10  26  41 
2011 
100 
26 20 29  25 100 16  13  21  51 
2012 
100 
30 20 28  23 NA 
NA NA NA  NA 
                                                 
110 The 287(g) program did not consistently record data on criminal offense levels prior to 2009, when DHS 
implemented new memorandums of understanding (MOAs) that included a three-level prioritizing scheme for the 
program. Under the 2009 MOAs, Level 1 offenders were defined as “aliens who have been convicted of or arrested for 
major drug offenses and/or violent offenses such as murder, manslaughter, rape, robbery, and kidnapping”; Level 2 
offenders as “aliens who have been convicted of or arrested for minor drug offenses, and/or mainly property offenses 
such as burglary, larceny, fraud, and money laundering”; and Level 3 offender as “aliens who have been convicted of 
or arrested for other offenses.” See “Memorandum of Agreement between ICE and the Harris County Sheriff’s Office,” 
October 29, 2009, http://www.ice.gov/doclib/foia/memorandumsofAgreementUnderstanding/
r_287gharriscountyso111609.pdf. The 2009 scheme was superseded by ICE’s agency-wide enforcement priority 
scheme beginning in March 2011, discussed above (“March 2011 ICE Guidance Memo”). 
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Source: Secure Communities data are based on CRS calculations from IDENT/IAFIS Interoperability Monthly 
Statistics through August 31, 2012; §287(g) data are based on CRS calculations from ICE Integrated Decision 
Support data as of August 8, 2011, received from ICE Legislative Affairs. 
Notes: 287(g) refers to agreements entered pursuant to INA §287(g) for jailing screening or task force 
programs; NA indicates “data not available.” §287(g) programs did not consistently col ect data on criminality 
levels prior to 2009; data are for a subset of §287(g) administrative arrests. See “March 2011 ICE Guidance 
Memo” and footnote 106 for definitions of criminality levels.  
It bears emphasis that these proportions are based on the subset of unauthorized aliens identified 
by the program who are placed under administrative arrest or who are removed or returned, and 
therefore overstate overall criminality levels. When accounting for the broader set of all 
removable aliens who are initially identified by Secure Communities, the data suggest that just 4-
6% of such aliens were convicted of criminal offenses prior to being removed or returned as a 
result of the program during the first nine months of FY2012.111 
How to evaluate these statistics is the subject of debate.112 On one hand, appropriators intended 
Secure Communities “to improve and modernize efforts to identify aliens convicted of a crime, 
sentenced to imprisonment, and who may be deportable” (emphasis added);113 and appropriators 
required DHS to “present a methodology … to identify and prioritize for removal criminal aliens 
convicted of violent crimes” (emphasis added).114 Some have argued that using ICE resources to 
identify and remove aliens who have not committed crimes or have only committed minor 
offenses and are not viewed as a threat to their communities diverts scarce resources away from 
high-priority cases.115  
On the other hand, appropriators also required DHS to “present a strategy for U.S. Immigration 
and Customs Enforcement to identify every criminal alien, at the prison, jail, or correctional 
institution in which they are held” (emphasis added).116 And as long as Secure Communities and 
related programs make serious criminals their top priority, nothing in the programs’ mandates 
appears to preclude a secondary focus on other removable aliens—a task that falls squarely within 
ICE ERO’s broader mission “to identify, arrest, and remove aliens who present a danger to 
                                                 
111 CRS estimates based on the ratio of convicted Level 1 (6%), Level 2 (4%), and Level 3 (5%) criminals removed or 
returned during the first nine months of FY2012 relative to the number of alien IDENT matches during the same period 
according to IDENT/IAFIS Interoperability Monthly Statistics through August 31, 2012, p. 2. The data are not precise 
percentages because they may refer to somewhat different groups of individuals identified and removed or returned 
during this period. 
112 A DHS task force convened to review Secure Communities found that “immigration enforcement against traffic 
offenders and others arrested only for minor offenses poses the greatest risk of undermining community policing” and 
recommended that ICE not issue detainers for individuals arrested solely for minor traffic offenses; but members of the 
task force were divided about whether ICE should also refuse to issue detainers for individuals arrested for other minor 
misdemeanors. See DHS Secure Communities Task Force Report, pp. 21-22. 
113  P.L. 110-161; 121 Stat. 2050. 
114  U.S. Congress, House Committee on Rules, Providing for the Consideration of the Senate Amendment to the bill H
.R.2764, Report to accompany H.R. 878, 110th Cong., 1st sess., December 17, 2007, H.Rept. 110-497 (Washington: 
GPO, 2008), p. 212. 
115 See, for example, John Morton, Memorandum on Civil Immigration Enforcement; also see U.S. Congress, House 
Committee on the Judiciary, Subcommittee on Immigration Policy and Enforcement, Oversight Hearing on U.S. 
Immigration and Customs Enforcement: Priorities and the Rule of Law, testimony of ICE Director John Morton, 112th 
Cong., 1st sess., October 12, 2011; U.S. Congress, Senate Committee on the Judiciary, Oversight of the Department of 
Homeland Security, testimony of DHS Secretary Janet Napolitano, 112th Cong., 1st sess., October 19, 2011. 
116  U.S. Congress, House Committee on Rules, Providing for the Consideration of the Senate Amendment to the bill H
.R.2764, Report to accompany H.R. 878, 110th Cong., 1st sess., December 17, 2007, H.Rept. 110-497 (Washington: 
GPO, 2008), p. 212. 
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national security or are a risk to public safety, as well as those who enter the United States 
illegally or otherwise undermine the integrity of our immigration laws and our border control 
efforts.”117 Many of the noncriminal aliens identified and removed or returned through Secure 
Communities program may be seen as high-priority cases for other reasons, including because 
they are the subject of a prior removal order or are recent unauthorized aliens. 
More generally, some Members of Congress have questioned why ICE would systematically 
exercise discretion in certain cases involving known unauthorized immigrants who are already in 
custody.118 Some Members of Congress have also suggested that the failure to remove certain 
non-criminal aliens identified by Secure Communities and related programs would constitute an 
“administrative amnesty” and could encourage further illegal immigration.119 
Involving State and Local Law Enforcement in Immigration-Related Screening 
May Harm Community-Police Relations 
ICE’s three jail enforcement programs interact in different ways with state and local law 
enforcement agencies, but all of them rely on such agencies, at least indirectly, as points of 
contact with potentially removable aliens as they are processed through the criminal justice 
system. By adding this filtering task to existing state and local law enforcement practices, jail 
enforcement programs may damage community-police relationships by undermining immigrant 
communities’ trust in state and local law enforcement agencies. Some law enforcement 
professionals have argued that if communities come to associate state and local law enforcement 
agencies with immigration enforcement, immigrants and others may be reluctant to report crimes 
or to cooperate in policing activities.120 Moreover, a DHS task force on Secure Communities 
found that the program “has had unintended local impacts” that may harm police relationships 
with immigrant communities.121 
Maintaining a good relationship and close partnerships with the community being served is a 
basic principle of community policing, a practice that has been adopted by many state and local 
law enforcement agencies, with the support of the Department of Justice.122 Some law 
enforcement professionals see community policing as particularly important with respect to 
immigrant communities because many immigrants come from countries and cultures without 
strong traditions of trust in law enforcement agencies; immigrants may already be fearful of 
interacting with law enforcement authorities due to concerns about their vulnerability to 
                                                 
117 U.S. Immigration and Customs Enforcement, ICE Enforcement and Removal Operations, http://www.ice.gov/about/
offices/enforcement-removal-operations/. 
118 See, for example, U.S. Congress, House Committee on Homeland Security, Subcommittee on Border and Maritime 
Security, Does Administrative Amnesty Harm our Efforts to Gain and Maintain Operational Control of the Border?, 
112th Cong., 1st sess., October 4, 2011; U.S. Congress, House Committee on the Judiciary, Subcommittee on 
Immigration Policy and Enforcement, Oversight Hearing on U.S. Immigration and Customs Enforcement: Priorities 
and the Rule of Law, 112th Cong., 1st sess., October 12, 2011. 
119 Ibid. 
120 See, for example, Chuck Wexler, “Critical Issues in Policing Series: Police Chiefs and Sheriffs Speak Out,” Police 
Executive Research Forum, April 2008, http://www.policeforum.org/library/critical-issues-in-policing-series/
Immigration($25).pdf; National Community Advisory Commission, Restoring Community. 
121 DHS Secure Communities Task Force Report, p. 24. 
122 U.S. Department of Justice, COPS: Community Oriented Policing Services, http://www.cops.usdoj.gov/Default.asp?
Item=34  
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immigration enforcement activities; and many immigrants are not proficient in English.123 
Immigrants are disproportionately likely to be victims of crime, and jail enforcement programs 
may discourage noncitizen crime victims from reporting crimes.124 Maintaining strong relations 
between immigrants and local law enforcement agencies also may strengthen the role of local law 
enforcement agencies in gathering intelligence about potential security threats associated with 
immigrant communities.125  
The risk that Secure Communities and related programs may harm community-police relations 
and discourage crime reporting must be balanced against the public safety benefit from 
identifying, detaining, and removing unauthorized aliens. While some state and local law 
enforcement officials see the threat to community relations as outweighing these potential 
benefits, as noted above, other state and local law enforcement officials and elected officials have 
embraced Secure Communities and the §287(g) program as powerful tools in their efforts to 
combat illegal immigration and associated criminal activity.126 
Involving State and Local Law Enforcement in Immigration-Related Screening 
May Contribute to Racial Profiling 
Critics argue that while the great majority of law enforcement officers are well-intentioned, 
involving state and local law enforcement agencies in immigrant enforcement may increase the 
likelihood that biased officers will engage in racial profiling, as that term is commonly 
understood.127 By ensuring that all arrestees are screened for immigration violations, jail 
enforcement programs may provide an incentive for officers to arrest persons they suspect of 
being unauthorized aliens based wholly or partly on racial or ethnic characteristics.  
                                                 
123  National Community Advisory Commission, Restoring Community; Debra A. Hoffmaster, Gerard Murphy, and 
Shannon McFadden, et al., Police and Immigration: How Chiefs are Leading Their Communities through the 
Challenges, Police Executive Research Forum, Washington, DC, 2010, http://www.policeforum.org/library/
immigration/PERFImmigrationReportMarch2011.pdf; U.S. Department of Justice, Enhancing Community Policing 
with Immigrant Populations: Recommendations from a Roundtable Meeting of Immigrant Advocates and Law 
Enforcement Leaders, New Orleans, LA, August 27, 2008, http://www.cops.usdoj.gov/files/RIC/Publications/
e041016266-enhancing-cp-immigrant-populations_b.pdf; US Department of Justice, Office of Justice Programs, 
Community Policing and ‘The New Immigrants’: Latinos in Chicago, Washington, DC, 1998, http://www.ncjrs.gov/
pdffiles1/nij/189908.pdf; Wexler, “Critical Issues in Policing.” 
124 Hoffmaster et al., Police and Immigration.  
125 David A. Harris, “The War on Terror, Local Police, and Immigration Enforcement: A Curious Tale of Police Power 
in Post-9/11 America,” Rutgers Law Journal, Vol. 38, No. 1 (Fall 2006); U.S. Department of Justice, Enhancing 
Community Policing. 
126 See for example Major County Sheriff’s Association, “Major County Sheriffs’ Association Resolution: Secure 
Communities,” http://www.ice.gov/doclib/secure-communities/pdf/sc-major_county_sheriffs_assoc.pdf; ICE, “What 
Others Are Saying About Secure Communities,” http://www.ice.gov/doclib/secure-communities/pdf/what-others-
say.pdf. 
127 See for example Rights Working Group, Faces of Racial Profiling: A Report from Communities Across America, 
Washington, DC, September 2010, http://www.rightsworkinggroup.org/sites/default/files/rwg-report-web.pdf; National 
Community Advisory Commission, Restoring Community. On legal issues surrounding the use of race as a factor in 
immigration enforcement also see CRS Report R41221, State Efforts to Deter Unauthorized Aliens: Legal Analysis of 
Arizona’s S.B. 1070, by Kate M. Manuel, Michael John Garcia, and Larry M. Eig. For a discussion of the definition of 
racial profiling see Jim Cleary, Racial Profiling Studies in Law Enforcement: Issues and Methodology, Minnesota 
House of Representatives Research Department, St. Paul, MN, June 2000, pp. 5-6, http://www.house.leg.state.mn.us/
hrd/pubs/raceprof.pdf;  
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ICE and supporters of Secure Communities have emphasized that because the program conducts 
immigration screening for all individuals arrested in participating jurisdictions, it does not lead to 
racial profiling.128 However, universal screening during the booking process does not necessarily 
prevent selective and potentially biased enforcement by law enforcement agents in the field. 
Officers may anticipate that arrestees will be subjected to immigration screening, and that some 
will be placed in removal proceedings regardless of the circumstances of their arrests. The DHS 
Secure Communities task force found that the program’s complaint procedures to guard against 
such profiling are inadequate.129 
Racial profiling is difficult to document, especially where jurisdictions may not collect detailed 
arrest and search data. Previous research by academic researchers and advocacy organizations has 
found evidence of racial profiling following the implementation of CAP and of immigration 
enforcement by local law enforcement agencies under the §287(g) program.130 Yet, most research 
on racial profiling is anecdotal rather than statistical, and CRS was unable to identify any 
published studies showing racial profiling in the Secure Communities program. 
Jail Enforcement Programs May Result in Wrongful Detentions  
Immigrant rights and civil liberties advocates have raised concerns about the use of immigration 
detainers to hold suspected unauthorized aliens who have not been charged with a crime.131 
Existing regulations permit immigration officers to issue an immigration detainer to request that a 
law enforcement jurisdiction hold an alien for up to 48 hours (not including weekends and 
holidays) in order to allow DHS to take custody of the alien and initiate removal proceedings, and 
that the jurisdiction notify DHS prior to releasing the alien; but several recently filed court cases 
have raised questions about ICE’s detainer authority.132  
Critics of Secure Communities and related programs have argued that no clear mechanisms exist 
for arrestees to challenge their detention on the grounds that they have been erroneously 
detained.133 Critics have also argued that no clear policies exist indicating how local law 
                                                 
128 See, for example, U.S. Congress, Senate Committee on Appropriations, Subcommittee on Homeland Security, 
Department of Homeland Security Appropriations Bill, 2012, Report to accompany H.R. 2017, 112th Cong., 1st sess., 
September 7, 2011, p. 59. 
129 DHS Secure Communities Task Force Report, p. 25. 
130  Trevor Gardner II and Aarti Kohli, The C.A.P. Effect: Racial Profiling in the ICE Criminal Alien Program, The 
Chief Justice Earl Warren Institute on Race, Ethnicity, and Diversity, Berkeley, CA, September 2009, 
http://www.law.berkeley.edu/files/policybrief_irving_0909_v9.pdf ; Azadeh Shahshahani et al., Terror and Isolation in 
Cobb: How Unchecked Police Power under 287(g) has Torn Apart Families and Threatened Public Safety, American 
Civil Liberties Union Foundation of Georgia, Atlanta, GA, October 2009, http://www.acluga.org/287gReport.pdf  
131 See, for example, National Community Advisory Commission, Restoring Community: A National Community 
Advisory Report on ICE’s Failed “Secure Communities Program, Washington, DC, August 2011, 
http://altopolimigra.com/documents/FINAL-Shadow-Report-regular-print.pdf; Alexa Alonzo, Kristin Macleod-Ball, 
and Greg Chen, et al., Immigration Enforcement Off Target: Minor Offenses with Major Consequences, American 
Immigration Lawyers Association, Washington, DC, August 2011, http://www.aila.org/content/fileviewer.aspx?docid=
36646&linkid=236762. 
132 See CRS Report R42690, Immigration Detainers: Legal Issues, by Kate M. Manuel. Also see 8 C.F.R. 287.7 
133 See, for example, Michele Waslin, The Secure Communities Program: Unanswered Questions and Continuing 
Concerns, The Immigration Policy Center, Washington, DC, November 2010, http://elpasotimes.typepad.com/files/
secure_communities_updated_110410-1.pdf.IPC Secure Communities report; Alonzo et al., Immigration Enforcement 
Off Target. 
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enforcement agencies should respond to ICE immigration detainers.134 In particular, the following 
concerns have been raised: that some local law enforcement agencies may treat ICE detainers as a 
requirement not to release an individual on bond even though he or she may otherwise be eligible 
for bond; that persons with ICE detainers may face added barriers to mount a defense against 
criminal charges; that detained individuals may face added detention time even if their criminal 
charges are dropped; and that detained individuals may be held for more than 48 hours.135  
Can Jurisdictions “Opt Out” of Secure Communities?  
Secure Communities was initially described as an optional program that offered state and local 
law enforcement agencies discretion about whether or not to participate.136 As with the §287(g) 
program, participation by local jurisdictions was initiated after a Memorandum of Agreement 
(MOAs) was negotiated between DHS and each state-level agency (typically, the state police or 
the state department of public safety) responsible for managing the interface between state law 
enforcement agencies and the FBI. According to the MOAs, “either party, upon 30 days written 
notice to the other party, may terminate the MOA at any time” or may “temporarily suspend 
activities … immediately upon receipt” of notification that resource constraints or competing 
priorities necessitate a suspension.137 
In light of this background, and partly because of the concerns described above, several 
jurisdictions have attempted to “opt out” of Secure Communities. In 2011, the governors of 
Illinois, New York, and Massachusetts announced that their states intended to rescind their Secure 
Communities MOAs. While the §287(g) program requires the active participation of a state or 
local partner, however, Secure Communities requires no active participation from local 
jurisdictions: it is simply an information-sharing system between two federal agencies. Thus, 
while the Obama Administration makes no claim that it can compel jurisdictions to forward 
information to the FBI for criminal background checks, the Administration has stated that 
jurisdictions cannot prevent the FBI from forwarding such data to DHS for immigration 
screening.138 An internal ICE memorandum written in October 2010 determined that the 
department had the authority to make Secure Communities a mandatory program without 
violating the Tenth Amendment to the U.S. Constitution.139 In August 2011, partly in response to 
states’ efforts to rescind their Secure Communities MOAs, ICE Director John Morton sent a letter 
to all state governors who had signed Secure Communities MOAs indicating that the agreements 
would be terminated and clarifying DHS’s position that jurisdictions may not opt out of Secure 
Communities.140  
                                                 
134 Ibid. 
135 Ibid. 
136 Shankar Vedantam, “No opt-out for immigration enforcement,” The Washington Post, October 1, 2010, Metro.; also 
see Waslin, The Secure Communities Program, pp. 11-12. 
137 ICE, Memorandum of Agreement between U.S. Department of Homeland Security Immigration and Customs 
Enforcement and State Identification Bureau, Washington, DC, http://www.ice.gov/doclib/foia/secure_communities/
securecommunitiesmoatemplate.pdf.http://www.ice.gov/foia/library/. 
138 ICE, “Secure Communities: Get the Facts,” http://www.ice.gov/secure_communities/get-the-facts.htm.  
139 Riah Ramlogan, Memorandum: Secure Communities—Mandatory in 2013, Washington, DC October 2, 2010. 
140  Tara Bahrampour, “Immigration Authority Terminates Secure Communities Agreements,” The Washington Post, 
August 7, 2011, http://www.washingtonpost.com/local/immigration-authority-terminates-secure-communities-
agreements/2011/08/05/gIQAlwx80I_story.html.; Daniel Gonzalez, “U.S. Immigration Officials Call of Deportation 
Agreement with States,” The Arizona Republic, August 6, 2011, http://www.azcentral.com/news/articles/2011/08/06/
(continued...) 
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With Secure Communities no longer operating under the state MOAs, some jurisdictions have 
attempted to limit their participation in the program by refusing to fully cooperate with ICE 
detainers issued as a result of the program. Citing concerns over both costs and wrongful 
detention, the Cook County, IL, Board of Commissioners, passed an ordinance in September 2011 
to require county jails to disregard immigration detainers unless the federal government agreed in 
advance to pay the associated detention costs.141 In 2012, the California legislature passed the 
TRUST Act, which would have directed law enforcement agencies in the state only to honor ICE 
detainers for arrestees with serious or violent felony convictions, but California Governor Jerry 
Brown vetoed the bill. In December 2012, California Attorney General Kamala Harris issued law 
enforcement guidance that ICE immigration detainers are not mandatory and directing law 
enforcement agencies in the state to make their own decisions about whether to honor such 
requests.142 The New York City Council also reportedly planned to propose new rules that would 
prevent the city from honoring ICE detainers unless an alien has been convicted of a previous 
felony or faces a felony charge, is included in a gang database or terrorist watchlist, or is the 
subject of an outstanding criminal warrant or a prior order of deportation.143 
ICE Has Taken Steps to Address Concerns About Secure 
Communities and the §287(g) Program  
ICE has implemented several changes to the §287(g) and Secure Communities programs designed 
in part to address the concerns described above. Beginning in July 2009, ICE required all law 
enforcement agencies participating in the §287(g) program to sign revised §287(g) 
Memorandums of Agreement (MOAs) as a condition for their continued participation in the 
program.144 The new MOAs were designed to strengthen ICE oversight of §287(g) enforcement 
and were accompanied by additional training requirements and the deployment of additional ICE 
supervisors to §287(g) jurisdictions. At the same time, after ICE supported the rapid expansion of 
the §287(g) program between 2007 and 2009, the agency established an internal advisory 
committee in 2009 in collaboration with the DHS Office of Civil Rights and Civil Liberties 
(CRCL). Under these new procedures, ICE has approved new §287(g) agreements at a much 
slower rate during 2010 and 2011.145 
                                                                  
(...continued) 
20110806federal-immigration-deportation-program-ends.html#ixzz1URNZ4FQ2.  
141  Chip Mitchell, “Illinois County Defies Feds on Immigrant Detainers,” National Public Radio, September 12, 2011, 
All Things Considered, http://www.npr.org/2011/09/12/140407306/cook-county-ill-bucks-immigration-enforcement; 
Don Babwin, “Cook County Defies Government on Immigration,” Associated Press, October 4, 2011, 
http://news.yahoo.com/cook-county-defies-government-immigration-184910659.html. 
142 Lee Romney and Cindy Chang, “Secure Communities is Optional, Harris Says,” Los Angeles Times, December 5, 
2012, http://articles.latimes.com/2012/dec/05/local/la-me-secure-communities-20121205. The legal question of 
whether or not states and localities can be required to comply with immigration detainers is a subject of ongoing 
litigation; see CRS Report R42690, Immigration Detainers: Legal Issues, by Kate M. Manuel. 
143 Kirk Semple, “2 Bills Before City Council Would Limit Deportations,” The New York Times, December 12, 2012. 
144 See ICE, Fact Sheet: Updated Facts on ICE’s 287(g) Program, September 7, 2011, http://www.ice.gov/news/
library/factsheets/287g-reform.htm; also see Capps, et al., Delegation and Divergence. 
145 According to ICE data, out of 69 current 287(g) agreements, one was signed in 2010, seven were signed in 2009, 30 
were signed in 2008, 23 were signed in 2007, and eight were signed in 2006 or earlier. 
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ICE also announced three major changes to the §287(g) program (in July 2009) and Secure 
Communities (in June 2011) designed to address each of the specific concerns raised above.146 
First, ICE has taken steps to impose agency-wide enforcement priorities on the §287(g) program 
and Secure Communities. The 2009 MOAs established a uniform three-level enforcement priority 
system for the §287(g) program, which was then superseded by the 2011 agency- and department-
wide memos and letter (see “DHS Enforcement Priorities and Discretion”). The 2011 guidance 
memos clarify ICE agents’ ability to exercise discretion throughout the immigration enforcement 
process, and ICE specifically linked the memos to Secure Communities by releasing them in the 
context of the other June 2011 reforms to that program.147 
The reforms also included the creation of a Homeland Security Advisory Council Task Force on 
Secure Communities composed of law enforcement professionals, ICE agents, and community 
and immigrant advocates. The task force’s goal was to recommend how to focus the program on 
high-priority offenders and ensure discretion in Secure Communities jurisdictions, among other 
issues.148 The task force issued a report with findings and recommendations in September 2011, 
and ICE published a formal response to the task force in April 2012.149 
Second, ICE has developed new record-keeping requirements and other tools to attempt to guard 
against pretextural arrests and racial profiling. ICE’s ENFORCE tracking system has been 
modified to track data on the circumstances leading to aliens’ arrests, information which may 
improve oversight of ICE’s partnership programs. ICE and CRCL have reportedly developed new 
statistical data to be collected on a quarterly basis to evaluate whether Secure Communities is 
being implemented in a biased way or otherwise resulting in racial profiling.150 The new §287(g) 
MOA also seeks to prevent pretextural arrests by requiring agencies to pursue all charges for 
which aliens are initially arrested. Nonetheless, media reports indicate that statistical monitoring 
of the Secure Communities program had been delayed as of November 2012, and that ICE may 
not be able to implement the statistical monitoring that had been announced in response to the 
Secure Communities task force recommendation.151 
Third, ICE and CRCL also have developed new materials and procedures to further reduce the 
risk of racial profiling and misuse of these enforcement programs.152 New training materials 
target ICE agents as well as local law enforcement agents involved in these programs. ICE and 
CRCL have also developed new immigration detainer forms clarifying that individuals should not 
be detained for more than 48 hours and that law enforcement agencies must provide detainees 
                                                 
146 On the 2009 announcement see ICE, “ICE Announces Standardized 287(g) Agreements with 67 state and Local 
Law Enforcement Partners,” press release, October 16, 2009, http://www.ice.gov/news/releases/0910/
091016washingtondc.htm; on the 2011 announcements, see Tara Bahrampour, “ICE Reforms Secure Communities 
Program,” Washington Post, June 17, 2011. 
147 ICE, Secure Communities: What’s New, http://www.ice.gov/secure_communities/. 
148 Ibid. 
149 ICE, Ice Responses to the Task Force on Secure Communities Findings and Recommendations, Washington, DC: 
April 27, 2012, http://www.ice.gov/doclib/secure-communities/pdf/hsac-sc-taskforce-report.pdf. 
150 Ibid. 
151 See for example, Alan Gomez, “Feds Delay Review of Obama Immigration Program,” USA Today November 5, 
2012. 
152 See ICE “DHS Plan to Provide Training to State and Local Law Enforcement in the Secure Communities Program,” 
May 2012, http://www.ice.gov/doclib/secure-communities/pdf/secure-communities-training-plan.pdf. 
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with information about how to file a complaint if they believe their civil rights have been 
violated.  
Legislative Issues 
In light of Congress’s long-standing support for programs targeting criminal aliens on the one 
hand, and the controversy surrounding some programs targeting criminal aliens on the other, 
Congress may consider several legislative issues related to Secure Communities and other ICE 
programs. 
The Role of State and Local Law Enforcement Agencies in 
Immigration Enforcement  
Congress considered legislation during the 112th Congress and may consider legislation in the 
future to clarify whether local jurisdictions have discretion to participate in Secure Communities. 
Several bills in the 112th Congress were introduced to support the expansion of Secure 
Communities by denying funding for various Department of Justice programs, including the State 
Criminal Alien Assistance Program (SCAAP), to jurisdictions that do not participate fully in 
Secure Communities and/or in other aspects of ICE’s Criminal Alien Program.153  
The question of whether states and localities have discretion to opt out of Secure Communities 
overlaps with a broader ongoing debate about the role of states and localities in immigration 
enforcement.154 Members of Congress have introduced legislation that would recognize that state 
and local officers have “inherent authority” to enforce federal immigration law,155 or, conversely, 
would establish that state and local officers may only enforce federal immigration law pursuant to 
a written agreement authorized under §287(g) of the INA.156 
Funding for the §287(g) program also was a point of contention during the FY2013 budget cycle 
and could be at issue in the 113th Congress. In its congressional budget justification for ICE, DHS 
proposed to reduce the budget for the §287(g) program by $17 million (a 25% reduction) with the 
expectation that the Secure Communities program would be fully deployed during FY2013, and 
because “the Secure Communities screening process is more consistent, efficient and cost 
effective in identifying and removing criminal and other priority aliens.”157 Thus, the department 
proposed to discontinue funding for the “least productive” existing task force agreements and to 
suspend consideration of new 287(g) task force requests.158 During the FY2013 funding cycle, the 
Senate Appropriations Committee supported the Administration’s proposed reductions to the 
program; but the House-passed H.R. 5855 maintained the FY2012 funding level of $68 million, 
                                                 
153 See, for example, the Strengthening Our Commitment to Legal Immigration and America’s Security Act (S. 332), 
H.R. 1274/S. 169, and the Enforce the Law for Sanctuary Cities Act (H.R. 1134). 
154 On legal questions surrounding state and local enforcement of immigration law see CRS Report R41423, Authority 
of State and Local Police to Enforce Federal Immigration Law, by Michael John Garcia and Kate M. Manuel. 
155 See, for example, Clear Law Enforcement for Criminal Alien Removal (CLEAR) Act of 2011 (H.R. 100). 
156 See, for example, Comprehensive Immigration Reform Act of 2011 (S. 1258). 
157 ICE, Congressional Budget Justifications FY2013, p. 76. Also see CRS Report R42644, Department of Homeland 
Security: FY2013 Appropriations, coordinated by William L. Painter. 
158 Ibid.  
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and an amendment adopted during House floor debate would prohibit any funds from the act 
being used to terminate an existing 287(g) agreement.159 
Prosecutorial Discretion 
Partly in response to the June 2011 ICE guidance memos and other Secure Communities reforms 
announced at the time,160 the House Judiciary Committee held a hearing in July 2011 on the 
Hinder the Administration’s Legalization Temptation (HALT) Act (H.R. 2497 in the 112th 
Congress).161 The HALT Act would have suspended for the remainder of President Obama’s term 
in office (i.e., through January 21, 2013) several provisions of law, including those authorizing 
cancellation of removal, parole, and deferred action.162 (The HALT Act also would have 
suspended a number of provisions of immigration law unrelated to prosecutorial discretion.) At 
the July 2011 hearing, supporters of the HALT Act described it as a tool to prevent an 
administrative amnesty, while opponents argued that prosecutorial discretion is a critical tool to 
prevent the misallocation of agency resources.163 The House Homeland Security and Judiciary 
Committees also held hearings on Prosecutorial Discretion on October 4, 2011, and October 12, 
2011, respectively;164 and Members questioned DHS officials about the deferred action for 
childhood arrivals (DACA) program165 during DHS oversight hearings.166 Other bills introduced 
in the 112th Congress would tighten the standards for parole and deferred action.167 Congress may 
continue to debate issues surrounding prosecutorial discretion and immigration enforcement in 
the 113th Congress.  
                                                 
159 Ibid. 
160 See, for example, Chairman Smith and Senator Vitter Introduce Bill to Stop Backdoor Amnesty, July 12, 2011, 
http://republicans.judiciary.house.gov/news/07122011.html.  
161  U.S. Congress, House Committee on the Judiciary, Subcommittee on Immigration Policy and Enforcement, 
Hearing on H.R. 2497, the “Hinder the Administration’s Legalization Temptation Act,” 112th Cong., 1st sess., July 26, 
2011. 
162 “Cancellation of removal” permits the Attorney General to cancel the removal of an alien who is inadmissible or 
deportable from the United States and adjust the alien’s status to an alien lawfully admitted for permanent residence 
(INA §240A(b)(1)); “parole” refers to the temporary admission of an alien for urgent humanitarian reasons or 
significant public benefit (INA §212(d)(5)(A)); and “deferred action” refers to a decision by DHS not to place a 
removable alien in removal proceedings or not to execute an order of removal (8 C.F.R. §274a.12(c)(14)).  
163  U.S. Congress, House Committee on the Judiciary, Subcommittee on Immigration Policy and Enforcement, 
Hearing on H.R. 2497, the “Hinder the Administration’s Legalization Temptation Act,” 112th Cong., 1st sess., July 26, 
2011. 
164 U.S. Congress, House Committee on Homeland Security, Subcommittee on Border and Maritime Security, Does 
Administrative Amnesty Harm our Efforts to Gain and Maintain Operational Control of the Border?, 112th Cong., 1st 
sess., October 4, 2011; U.S. Congress, House Committee on the Judiciary, Subcommittee on Immigration Policy and 
Enforcement, Hearing on U.S. Immigration and Customs Enforcement: Priorities and the Rule of Law,” 112th Cong., 
1st sess., October 12, 2011. 
165 In June, 2012, DHS announced that certain individuals who were brought to the United States as children and met 
other criteria would be considered for deferred action for two years, subject to renewal. See U.S. Department of 
Homeland Security, Memorandum to David V. Aguilar, Acting Commissioner, U.S. Customs and Border Protection, 
Alejandro Mayorkas, Director, U.S. Citizenship and Immigration Services, John Morton, Director, U.S. Immigration 
and Customs Enforcement, from Janet Napolitano, Secretary of Homeland Security, Exercising Prosecutorial 
Discretion with Respect to Individuals Who Came to the United States as Children, June 15, 2012. 
166 See for example, U.S. Congress, House Committee on the Judiciary, Oversight Hearing: Department of Homeland 
Security, 112th Congress, 2nd sess., July 19, 2012. 
167 See for example the Strengthening Our Commitment to Legal Immigration and America’s Security Act (S. 332).  
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Data on Racial Profiling 
Congress may consider legislation that would mandate new data collection in response to 
concerns about whether state and local participation in Secure Communities leads to racial 
profiling or interferes with police-community relations. In the 112th Congress, the Traffic Stops 
Along the Border Statistics Study Act (H.R. 228), for example, would require the Attorney 
General to conduct a nationwide study of stops for traffic violations by law enforcement officers; 
perform an initial analysis of existing data, including complaints alleging, and information 
concerning, traffic stops motivated by race and other bias; and gather specified data from a 
nationwide sample of jurisdictions, including the traffic infraction alleged to have been 
committed that led to the stop, characteristics of the driver stopped, whether immigration status 
was questioned, and whether any warning or citation was issued as a result of the stop. Such data 
collection could give Congress and the Department of Justice additional information about 
whether Secure Communities and other ICE programs targeting criminal aliens contribute to 
racial profiling. 
Immigration Detainers  
Congress also may consider legislation to provide clearer statutory authority for states and 
localities to detain an unauthorized alien until DHS takes custody of the alien and initiates 
removal proceedings—an issue that has received increased attention given the growing number of 
removable aliens identified by Secure Communities and recent court cases. Currently, DHS has 
explicit statutory authority to issue immigration detainers for controlled substance offenses,168 and 
regulations authorize the issuance of immigration detainers to any alien in the custody of a 
federal, state, or local law enforcement agency in other circumstances.169 Regulations limit 
immigration detainers to 48 hours, excluding weekends and holidays.170 There is some question 
about whether or not jurisdictions are required to honor detainer requests.171 The 112th Congress 
considered legislation to broaden the authority of state officials to issue immigration detainers 
and to allow aliens to be detained for up to 14 days;172 and Congress may consider legislation to 
grant DHS express statutory to issue detainers for some or all offenses, to clarify limits on the 
agency’s detainer authority, and/or to link certain federal funding to compliance with ICE 
detainers. 
Conclusion 
The Immigration and Nationality Act requires the expeditious removal of certain criminal aliens, 
and Congress views such enforcement as a priority. Administrative programs aimed at removing 
criminal aliens have come under criticism because these programs also target noncriminal aliens 
and aliens with a limited criminal record (i.e., nonviolent criminal aliens). Proponents maintain, 
however, that targeted aliens have violated U.S. law.  
                                                 
168 8 U.S.C. §1357(d). 
169 8 C.F.R. §287.7(a). 
170 8 C.F.R. §287.7(d). 
171 See CRS Report R42690, Immigration Detainers: Legal Issues, by Kate M. Manuel. 
172 See for example in the 112th Congress, the Criminal Alien Removal Act of 2011 (H.R. 932). 
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Incarcerated noncitizens provide a rough measure of the criminal alien population, although 
inconsistencies in data quality, data collection practices, and definitions hinder its precise 
quantification. According to the most recently available published statistics, an estimated 173,000 
noncitizens were incarcerated in 2009, distributed roughly equally across federal and state prisons 
and local jails. They represented 7.2% of the total incarcerated population of 2.4 million, a 
proportion similar to the noncitizen proportion of the foreign-born population. Data from the 
American Community Survey yield a similar estimate for that year. Nationally, incarcerated 
persons represent just one-third of the total correctional population, with persons on probation 
and parole comprising the other two-thirds. 
The four main programs targeting criminal aliens have seen a 25-fold funding increase between 
FY2004 and FY2012, and the number of aliens arrested through these programs has increased by 
a similar proportion. These programs, however, have been controversial, particularly the §287(g) 
program and Secure Communities, both of which rely on direct or indirect partnerships with state 
and local law enforcement authorities.  
Arguments favoring and opposing these programs have been clearly articulated. On the one hand, 
the majority of potentially removable aliens identified by Secure Communities and the §287(g) 
program are not violent criminal aliens. DHS programs that rely on partnerships with state and 
local law enforcement agencies may risk damaging relations between immigrant communities 
and local police and may also lead to racial profiling and wrongful detention.  
On the other hand, DHS must conduct robust interior enforcement if it is to remove a substantial 
proportion of unauthorized aliens living in the United States—now estimated at 10.8 million 
people. Partnerships with state and local law enforcement agencies greatly expand DHS’s 
enforcement capacity. By relying on existing technology and centralized screening, Secure 
Communities is an especially efficient way to identify and detain a large number of potentially 
removable aliens passing through the criminal justice system. These programs appear to be 
valuable tools in ICE’s overall detention and removal operations. Moreover, DHS has taken steps 
to minimize the unintended consequences of Secure Communities, including issuing new 
guidance on prosecutorial discretion to ensure that its resources target high-priority cases.  
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Appendix A. Glossary of Terms  
Despite its widespread use, no consistent definition of the term “criminal alien” exists. In this 
report, CRS uses “criminal aliens” to refer to any noncitizen who has ever been convicted of a 
crime. Certain crimes also have immigration-related consequences, such as being grounds for 
removal, and certain categories of criminal (and noncriminal) aliens are also the subjects of 
special ICE enforcement programs, including those described in this report. The following terms 
are often discussed in the context of these programs. Definitions are based on CRS’s analysis of 
statutory definitions where noted and of DHS usage and prevailing definitions in other cases. 
Absconder: See “fugitive alien.”  
Aggravated felon: A noncitizen who has been convicted of an aggravated felony (see below); 
aggravated felons are subject to removal from the United States, ineligible for certain forms of 
immigration relief, and ineligible to be readmitted to the United States.  
Aggravated felony: A crime identified in §101(a)(43) of the Immigration and Nationality Act 
(INA), a list that includes numerous state and federal offenses ranging from murder, rape, and 
trafficking in controlled substances to theft, bribery, and obstruction of justice. Crimes committed 
outside the United States may also be considered aggravated felonies if the term of imprisonment 
was completed within the previous 15 years.  
At-large criminal alien: A noncitizen who has been convicted of a crime in the United States and 
is not currently incarcerated. Not all at-large criminal aliens are removable. 
Criminal alien: A noncitizen who has been convicted of a crime in the United States. Not all 
criminal aliens are removable. 
Criminal immigration offense: A violation of federal criminal immigration law under Title 8 or 
Title 18 of the U.S. Code. The most common such violations for which aliens are convicted are 8 
U.S.C. §1326 (reentry of a deported alien), 8 U.S.C. §1324 (bringing in and harboring certain 
aliens), 15 U.S.C. §1546 (fraud and misuse of visas, permits, and other documents), and 8 U.S.C. 
§1325 (entry of alien at improper time or place). 
Fugitive alien: An alien who has failed to leave the United States following the issuance of a 
final order of removal, deportation, or exclusion. Fugitive aliens were referred to as “absconders” 
prior to FY2007. 
Removable alien: An alien subject to formal removal (deportation) from the United States. This 
includes aliens who are inadmissible under INA §212 or deportable under INA §237, including 
nonimmigrant aliens who enter legally but violate the terms of their visas or overstay their visas. 
Most removable aliens have never been convicted of a criminal offense. 
Removable criminal alien: An alien who has been convicted of a removable criminal offense; 
such an alien is subject to removal from the United States. 
Removable criminal offense: A criminal offense described in §237(a)(2) of the Immigration and 
Nationality Act (INA), including crimes of moral turpitude, aggravated felonies, high-speed flight 
from an immigration checkpoint, failure to register as a sex offender, drug offenses, firearm 
offenses, and immigration-related document fraud, among others. 
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Appendix B. Data on Arrests and Incarceration of 
the Criminal Alien Population 
Data Analyzed 
At the federal level, arrest data are compiled by the U.S. Marshals Service (USMS) Prisoner 
Tracking System and published by the Department of Justice (DOJ) Bureau of Justice Statistics 
(BJS) through its online Federal Justice Statistics Resource Center (FJSRC).173 Federal 
incarceration data are published by the Federal Bureau of Prisons (BOP) and complied by the 
Sourcebook of Criminal Justice Statistics. 
Figures for the federal and state noncitizen prison population from 2001-2008 are as of year-end 
and include sentenced as well as non-sentenced inmates, and inmates under jurisdiction as well as 
inmates in custody. In contrast, figures for the local noncitizen jail population for all years (2001-
2009) were only available for mid-year. These mid-year figures only include sentenced inmates 
and inmates in custody. For 2009, however, federal and state figures for the noncitizen 
incarcerated population were available only as of midyear. Hence, all 2009 figures – federal, 
state, and local – are as of mid-year. As of December 2012, published data on the noncitizen 
incarcerated population for 2012 were unavailable at the state and local levels. 
State incarceration data come from annually published BJS reports, Prison Inmates at Midyear. 
Data for that report come from the National Prisoner Statistics (NPS) program of BJS, which 
obtains mid-year and year-end prisoner counts from correctional departments of all 50 states.  
BJS also conducts an Annual Survey of Jails, from which it creates national-level estimates of the 
number of inmates incarcerated in local jails.174 In addition, it conducts a complete count of the 
local jail population every five years through its Census of Jails. Together, these two local jail 
counts provide a consistent annual series of the total number of persons incarcerated in local jails, 
though these local data are problematic, as described below.  
Data Quality and Limitations 
Several obstacles challenge and limit the ability of researchers to accurately enumerate the 
criminal alien population or compare its criminal activity to other U.S. populations. 175 For 
example, while federal BOP data include information on citizenship status, not all state and local 
criminal justice systems collect such information, creating substantial inconsistencies in data 
quality and completeness at the state and local level. There is no single and consistent national 
enumeration of prisoners in the United States similar to the decennial census or the Current 
                                                 
173 PTS contains data on suspects arrested for violations of federal law, by federal enforcement agencies and data about 
warrants initiated or cleared. The data include information on characteristics of federal arrestees. See page 107 of 
http://bjs.ojp.usdoj.gov/content/pub/pdf/cfjs0407.pdf.  
174 Jail administrators are asked whether they are holding any inmates for the Immigration and Customs Enforcement 
(ICE) agency. 
175  For more information on data challenges for quantifying the criminal alien population, see Steven A. Camarota and 
Jessica M. Vaughan, Immigration and Crime: Assessing a Conflicted Issue, Center for Immigration Studies, 
Washington, DC, November 2009, http://www.cis.org/articles/2009/crime.pdf. 
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Population Survey—much less one that focuses on subpopulations such as noncitizens.176 Hence, 
attempts to quantify the U.S. criminal alien population have relied on estimation techniques, 
assumptions about the criminal alien proportion of the total criminal population, and federal 
surveys and censuses of prison inmates. This section discusses several data limitations associated 
with collecting data at the various stages of the criminal justice system.  
Arrests and Incarcerations Are Imperfect Indicators of Immigrant Criminality 
Arrests and incarcerations are both imperfect measures of criminality. Arrest data overestimate 
criminality because some individuals who are arrested are subsequently released, or if charged, 
are not ultimately convicted. And local incarceration data also over-count certain individuals 
because some people are incarcerated in local jails even though they have not yet been charged or 
convicted of crimes. 
Conversely, incarceration data generally underestimate the total number of convicted criminals 
because they exclude persons on parole and persons sentenced to probation. For instance, of the 
7,076,200 individuals included by BJS in its 2010 estimate of the total correctional population, 
4,055,514 were on probation, 840,676 were on parole, and 2,262,832 were incarcerated in federal 
and state prisons or in local jails.177  
One also must use caution when examining arrest and incarceration data because greater (or 
lesser) numbers of arrests and incarcerations do not always indicate an increase (or decrease) in 
criminal activity. They may indicate changes in enforcement policy. For instance, a reduction in 
arrests or incarcerations for illegal immigration entry may stem from fewer persons attempting to 
enter the United States illegally, but it may also reflect changes in resources or enforcement 
priorities. It is also noteworthy that some crimes are never reported: arrests and incarcerations 
only reflect the number of offenses known to law enforcement.  
Inconsistent State and Local Data Reporting 
In addition to these limitations with respect to data validity, efforts to estimate the criminal alien 
population also confront a significant limit with respect to data availability and reliability. First, 
there are no recent and complete publicly available data on arrests at the state and local levels that 
distinguish between U.S. citizens and noncitizens.178 Thus, this report limits its analysis of arrest 
data to federal statistics. 
                                                 
176 Hagan and Palloni, 1999. 
177  U.S. Department of Justice, Bureau of Justice Statistics, Sourcebook of criminal justice statistics Online, 
Washington, DC, 2010, http://www.albany.edu/sourcebook/pdf/t612009.pdf. In this particular series, counts for 
probation, prison, and parole populations are for December 31, and jail population counts are as of June 30. In general, 
any over- or under-count of the criminal alien population also applies to the native-born population. Hence the degree 
to which the proportion of criminal aliens changes relative to other criminal populations by using these imperfect 
metrics depends on the likelihood that aliens are sentenced to probation or released on parole (or arrested and not 
charged with crimes) relative to other criminal populations. 
178 Recent public-use data on criminal aliens can be obtained from two sources: the U.S. Department of Justice’s 
Bureau of Justice Statistics, which publishes the annual Prison and Jail Inmates at Midyear report, and the National 
Archive of Criminal Justice Data (NACJD), which provides to the public the raw data for analysis. The aggregation of 
state and local level criminal justice data into meaningful datasets requires consistent definitions of specified 
populations and criminal activities, as well as consistent reporting practices. Moreover, it often relies on the voluntary 
participation of state criminal justice agencies. Definitional inconsistencies, reporting differences, and differing 
(continued...) 
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Second, BJS’s state and local incarceration data are based on the voluntary participation of each 
state’s department of corrections and local jails. While all states contribute data to BJS on their 
prison population, states vary with respect to how they define terms, which poses challenges to 
estimating the size and character of the criminal alien population. For instance, some states report 
foreign-born prisoners and naturalized U.S. citizens rather than strictly noncitizens, potentially 
inflating counts of the criminal alien population.179 
Local jail reporting practices are likely to be even more inconsistent than state practices given the 
far greater number of jurisdictions. And not all local jurisdictions even report on their foreign-
born criminal populations. For these reasons, GAO concluded in 2005 that “there [are] no reliable 
population ... data on criminal aliens incarcerated in all state prisons and local jails.”180 
Additional Sources of Bias 
Several additional factors may impede efforts to quantify the criminal alien population. Because 
criminal activity can lead to removal, criminal aliens could have strong incentives to lie about 
their legal status or not to provide such information, although biometric technology increasingly 
permits authorities to identify certain removable aliens. Furthermore, serious crime is frequently 
intra-racial and intra-ethnic in nature. Unauthorized alien victims may be particularly reluctant to 
report crime for fear that contact with the criminal justice system may result in their own 
removal.181 Such behavior can have nontrivial effects on crime reporting in some jurisdictions, 
given the frequent intra-racial and intra-ethnic character of serious crime.182 
Presentation of Publicly Available Data 
A separate data-related complication independent of data quality concerns differences between 
counts of criminal justice data that result from factors such as whether the data come from mid-
year or year-end, include persons in privately operated community facilities, include persons 
convicted in Washington DC, and similar variations. In addition, differences can occur between 
analyzing raw data and defining criminal aliens with certain decision rules, versus using data 
published online by BOP that incorporate different decision rules. For instance, figures on 
federally incarcerated criminal aliens in this report differ slightly from those presented in the 
GAO report, although it is not clear from the GAO report or from the source for data contained in 
this CRS report how those different figures would be reconciled. 
 
 
                                                                  
(...continued) 
participation levels all reduce the reliability and comparability of state level data on the criminal alien population.  
179  Bureau of Justice Statistics, Prison Inmates at Midyear 2009 - Statistical Tables, U.S. Department of Justice, 
Washington, DC, June 2010, p. 23, http://bjs.ojp.usdoj.gov/content/pub/pdf/pim09st.pdf. 
180 GAO, Information on Criminal Aliens Incarcerated in Federal and State Prisons and Local Jails, p.2.  
181  Orde F. Kittrie, “Federalism, Deportation, and Crime Victims Afraid to Call the Police,” Iowa Law Review, vol. 91 
(2005), pp. 1449-1508. 
182 Ibid. 
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Author Contact Information 
 
Marc R. Rosenblum 
  William A. Kandel 
Specialist in Immigration Policy 
Analyst in Immigration Policy 
mrosenblum@crs.loc.gov, 7-7360 
wkandel@crs.loc.gov, 7-4703 
 
 
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