Primer on U.S. Immigration Policy

Primer on U.S. Immigration Policy
July 1, 2021
U.S. immigration policy is governed largely by the Immigration and Nationality Act (INA),
which was first codified in 1952 and has been amended significantly several times since. U.S.
William A. Kandel
immigration policy contains two major aspects. One facilitates migration flows into the United
Analyst in Immigration
States according to principles of admission that are based upon national interest. These broad
Policy
principles currently include family reunification, U.S. labor market contribution, origin-country

diversity, and humanitarian assistance.

The United States has long distinguished permanent from temporary immigration. Permanent
immigration occurs through family and employer-sponsored categories, the diversity immigrant visa lottery, and refugee and
asylee admissions. Temporary immigration occurs through the admission of foreign nationals for specific purposes and
limited periods of time, and encompasses two dozen categories that include foreign tourists, students, temporary workers, and
diplomats.
The other major aspect of U.S. immigration policy involves restricting entry to and removing persons from the United States
who lack authorization to be in the country, are identified as criminal aliens, or whose presence in the United States is
determined to not serve the national interest. Such immigration enforcement is broadly divided between border
enforcement—at and between U.S. land, air, and sea ports of entry—and other enforcement tasks including interior
enforcement, detention, removal, worksite enforcement, and combatting immigration fraud.
The dual role of U.S. immigration policy—admissions and enforcement—creates challenges for balancing major policy
priorities, such as ensuring national security, facilitating trade and commerce, protecting public safety, and fostering
international cooperation.

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Contents
Introduction ................................................................................................................... 1
Immigration Inflows and Related Topics............................................................................. 1

Permanent Immigration .............................................................................................. 2
Family-Sponsored Immigration .............................................................................. 3
Employment-Based Immigration ............................................................................ 3
Requirements for Prospective Immigrants ................................................................ 4
Visa Queue.......................................................................................................... 5
Diversity Immigrant Visa....................................................................................... 5
Refugees and Asylees ........................................................................................... 5
Other Pathways to Lawful Permanent Resident Status................................................ 6
Temporary Immigration .............................................................................................. 7
Requirements for Temporary Admission .................................................................. 8
Border Crossing Card ........................................................................................... 8
Visa Issuance and Security .......................................................................................... 9
Visa Waiver Program .......................................................................................... 10
Types of “Quasi-legal” Status .................................................................................... 11
Temporary Protected Status ................................................................................. 11
Parole ............................................................................................................... 11
Naturalization ......................................................................................................... 12
Immigration Enforcement............................................................................................... 12
Border Security at Ports of Entry................................................................................ 12
Border Security Between Ports of Entry ...................................................................... 13
Detention ............................................................................................................... 15
Removal ................................................................................................................ 16
Programs Targeting Criminal Aliens ...................................................................... 17
Options for Aliens in Removal Proceedings ............................................................ 17

Worksite Enforcement .............................................................................................. 19
Combatting Immigration Fraud.................................................................................. 19

Unauthorized Aliens ...................................................................................................... 19

Tables
Table 1. Family-Sponsored Immigrant Categories ................................................................ 3
Table 2. Employment-Based Immigrant Categories .............................................................. 4

Contacts
Author Information ....................................................................................................... 21

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Introduction
This report provides a broad overview of U.S. immigration policy. The first section addresses
policies governing how foreign nationals enter the United States to either reside permanently or
stay temporarily. Related topics within this section include visa issuance and security, forms of
quasi-legal status, and naturalization. The second section discusses enforcement policies both for
excluding foreign nationals from admission into the United States, as wel as for detaining and
removing those who enter the country unlawfully or who enter lawfully but subsequently commit
crimes that make them deportable. The section also covers worksite enforcement and immigration
fraud. The third section of this report addresses policies for unauthorized aliens1 residing in the
United States. While intended to be comprehensive, this primer may omit some immigration-
related topics. For example, it general y does not discuss policy issues or congressional concerns
about specific immigration-related policies and programs.
Immigration Inflows and Related Topics
U.S. immigration policy is governed largely by the Immigration and Nationality Act (INA),
which was first codified in 1952 and has been amended significantly several times since.2
Implementation of INA policies is carried out by executive branch agencies. The Department of
Homeland Security (DHS) has primary responsibility for immigration functions through several
agencies: U.S. Citizenship and Immigration Services (USCIS), U.S. Customs and Border
Protection (CBP), and U.S. Immigration and Customs Enforcement (ICE). The Department of
State (DOS) issues visas to foreign nationals overseas, and the Department of Justice (DOJ)
operates immigration courts through its Executive Office for Immigration Review (EOIR). The
Department of Labor (DOL) operates a foreign labor certification program to ensure that foreign
workers do not displace or adversely affect working conditions of U.S. workers.
This report uses specific terms to refer to foreign-born populations having different legal statuses.
The legal term aliens refers to people who are not U.S. citizens, including those both legal y and
not legal y present. The two main types of aliens lawfully present in the United States are (1)
immigrants (this term excludes refugees and asylees) and (2) nonimmigrants. Immigrants refers
to foreign nationals lawfully admitted to the United States for permanent residence.3
Nonimmigrants refers to foreign nationals lawfully and temporarily admitted to the United States
for a specified purpose and period of time, including tourists, diplomats, students, temporary
workers, and exchange visitors, among others.
The terms refugees and asylees identify individuals who are not formal y classified as immigrants
under the INA and refer to persons who are outside of their home countries and unable or
unwil ing to return because of persecution, or a wel -founded fear of persecution, on account of
race, religion, nationality, membership in a particular social group, or political opinion (see
“Refugees and Asylees”).4 Once admitted, refugees and asylees may apply to adjust to lawful
permanent resident (LPR) status.
Naturalized citizens refers to LPRs who become U.S. citizens through a process known as
naturalization (described below), general y after residing in the United States continuously for at

1 T he INA defines alien as a person who is not a citizen or a national of the United States. See INA §101(a)(3). In this
report, the terms alien, foreign national, and noncitizen are synonymous.
2 T he INA (P.L. 82-414) is Act of June 27, 1952, ch. 477, codified, as amended, at 8 U.S.C. §§1101 et seq.
3 In this report, the terms immigrant, lawful permanent resident (LPR), and green card-holder are synonymous.
4 INA §101(a)(42), 8 U.S.C. §1101(a)(42).
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least five years. Noncitizens are persons who have not naturalized and may include immigrants as
wel as nonimmigrants.
Unauthorized aliens refers to foreign nationals who reside unlawfully in the United States. They
either entered the United States il egal y (without inspection) or entered lawfully and temporarily
(with inspection) but subsequently violated the terms of their admission, typical y by overstaying
their visa duration.5
Permanent Immigration6
Four general principles underlie the current system of permanent immigration: family
reunification, U.S. labor market contribution, origin-country diversity, and humanitarian
assistance. These principles are reflected in different components of permanent immigration.
Family reunification occurs primarily through family-sponsored immigration. U.S. labor market
contribution occurs through employment-based immigration. Origin-country diversity is
addressed through the Diversity Immigrant Visa. Humanitarian assistance occurs primarily
through the U.S. refugee and asylee programs. These permanent immigration pathways are
discussed further below.
The INA limits worldwide permanent immigration to 675,000 persons annual y: 480,000 family-
sponsored immigrants,
made up of immediate relatives of U.S. citizens, and a set of ordered
family-sponsored preference immigrants (preference immigrants); 140,000 employment-based
immigrants; and 55,000 diversity visa immigrants.7 This worldwide limit, however, is referred to
as a permeable cap because immediate relatives are exempt from numerical limits placed on
family-sponsored immigration (described below) and thereby represent the flexible component of
the 675,000 worldwide limit. In addition, the annual number of refugees is determined not by
statute but by the President, in consultation with Congress. Asylees are adjudicated on a case-by-
case basis without a statutorily mandated limit (see “Refugees and Asylees”). Consequently,
actual total annual LPRs (immigrants, refugees, and asylees) have exceeded 1 mil ion persons in
al but 4 of the past 20 years.
To ensure that foreign nationals from only a few countries do not dominate permanent
immigration flows, the INA further specifies a 7% per-country limit on the number of family-
sponsored preference immigrants and employment-based immigrants from a single country.8

5 Also counted in this population are persons with parole or other forms of quasi-legal status (described below).
6 In this report, the term admissions broadly refers to the entry of aliens into the United States, either permanently or
temporarily. T echnically, aliens who immigrate permanently do so either by being adm itted as LPRs (if arriving from
abroad) or by adjusting status from a temporary nonimmigrant status to LPR status (if residing in the United States).
For more information on permanent immigration, see CRS Report R42866, Perm anent Legal Im migration to the
United States: Policy Overview
.
7 See, respectively, INA §201(c), INA §201(d), and INA §201(e). While the diversity visa category has not been
directly amended since its enactment, the Nicaraguan Adjustment and Central American Relief Act of 1997
(NACARA; P.L. 105-100) temporarily reduced the 55,000 annual ceiling beginning in FY1999 by up to 5,000 annually
to offset immigrant numbers made available to certain unsuccessful asylum seekers from El Salvador, Gua temala, and
formerly communist countries in Europe. T he 5,000 offset is nearing an end; for FY2021, the reduction was limited to
approximately 150.
8 For more background, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy Overview.
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Family-Sponsored Immigration
Family-sponsored immigration consists of two immigrant groups (Table 1). Immediate relatives
include spouses and minor unmarried children of U.S. citizens and parents of adult U.S. citizens.
Immediate relatives are not subject to annual numerical limits and can acquire LPR status if they
meet the standard eligibility criteria required of al immigrants. Preference immigrants, on the
other hand, are numerical y limited to 226,000 per year and, unlike immediate relatives, are also
bounded by the 7% per-country limit.9 In recent years, family-sponsored immigrants have
accounted for roughly two-thirds of al persons receiving LPR status.10
Table 1. Family-Sponsored Immigrant Categories
Category
Individuals in Category
Immediate Relatives

Spouses and unmarried minor children of U.S. citizens, and parents of adult U.S. citizens
Preference Immigrants
1st Preference
Unmarried adult children of U.S. citizens
2nd Preference
(A) Spouses and minor children of LPRs

(B) Unmarried adult children of LPRs
3rd Preference
Married adult children of U.S. citizens
4th Preference
Siblings of adult U.S. citizens
Source: INA §§203(a)(b), 8 U.S.C. §§1153(a)(b).
Note: LPR = lawful permanent resident.
Employment-Based Immigration
Employment-based immigration occurs through five numerical y limited preference categories
(Table 2), the first three of which are based on professional accomplishment and ability. The
fourth preference category includes various “special immigrants.”11 The fifth preference category
is for immigrant investors, a category created in 1990 to benefit the U.S. economy through
employment creation and capital investment.12 Employment-based immigrants also include
accompanying spouses and children; are limited to 140,000 total annual admissions; and are

9 When the demand for such visas exceeds 226,000, the 226,000 limit also acts as a floor, below which the number of
family preference immigrants cannot fall. More than 226,000 family preference immigrants can be admitted under
current law only if the number of immediate relatives admitted, less the number of any unused employment -based
preference numbers from the prior year, is fewer than 254,000 (the difference between 480,000 and 226,000).
However, annual admissions of immediate relatives less unused employment -based preference numbers from the prior
year have exceeded 254,000 every year since 2001. For instance, in FY2019 (the most recent year for which data are
available), immediate relatives totaled 505,765. T hus, under these statutory constraints, family-sponsored preference
category immigrants are effectively limited to 226,000 per year.
10 For more background, see CRS Report R43145, U.S. Family-Based Immigration Policy.
11 For a complete list of special immigrant categories, see USCIS, “Special Immigrants,” at https://www.uscis.gov/
humanitarian/special-immigrants.
12 T he EB-5 visa was created through the Immigration Act of 1990 (P.L. 101-649). For more background, see CRS
Report R44475, EB-5 Im m igrant Investor Visa.
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subject to the same 7% per-country limit for each preference category as family-sponsored
preference immigrants.13
Table 2. Employment-Based Immigrant Categories
Category
Individuals in Category
1st Preference
Priority workers: persons of extraordinary ability in the arts, sciences,
education, business, or athletics; outstanding professors and researchers; and
certain multinational executives and managers
2nd Preference
Members of the professions holding advanced degrees or persons of
exceptional ability in the sciences, arts, or business
3rd Preference (skil ed)
Skil ed shortage workers with at least two years training or experience, and
professionals with baccalaureate degrees
3rd Preference (unskil ed)
Unskil ed shortage workers
4th Preference
“Special immigrants,” including ministers of religion, religious workers other
than ministers, certain employees of the U.S. government abroad, and others
5th Preference
Employment creation investors who invest at least $1.8 mil ion ($900,000 in
rural areas or areas of high unemployment) and create/preserve at least 10 jobs
Source: INA §204, 8 U.S.C. §1154.
Requirements for Prospective Immigrants
To obtain LPR status, prospective immigrants must traverse a multistep process through several
federal departments and agencies.14 If they already reside legal y in the United States, obtaining
LPR status involves adjusting status from a temporary nonimmigrant status to lawful permanent
resident status. If they live abroad and have not established a lawful residence in the United
States, they must apply for an immigrant visa. Al family-based immigrants and most
employment-based immigrants require that a relative or an employer, respectively, petition on
their behalf. Petitions filed in the United States are adjudicated by USCIS. Petitions filed from
overseas are forwarded to DOS’s Bureau of Consular Affairs in the prospective immigrant’s
home country for immigrant visa processing after they have been adjudicated by USCIS.
For al prospective immigrants, USCIS and the consular officer (when the alien lives abroad) or
the USCIS adjudicator (when the alien is adjusting status within the United States) must be
satisfied the alien is entitled to the immigrant status. These reviews are intended to ensure that
prospective immigrants are not ineligible for visas or admission under the INA’s grounds for
inadmissibility (see the “Visa Issuance and Security” section).
When a visa becomes available, it al ows an approved prospective immigrant to travel to the
United States and, if admitted to the country by an immigration officer at a port of entry, receive
LPR status. If the approved prospective immigrant already resides in the United States on a
nonimmigrant visa, the availability of a visa (in this case, an LPR slot) al ows him/her to adjust
status.
Adjusting status permits a temporary nonimmigrant to become a permanent immigrant
without having to return to his/her country of origin to complete visa processing through a DOS
consulate.

13 For more information, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy
Overview
.
14 For more information, see CRS Report R42866, Permanent Legal Immigration to the United States: Policy
Overview
.
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Visa Queue
The number of foreign nationals seeking to immigrate to the United States each year through
family-sponsored and employment-based preference categories typical y exceeds the INA-
mandated numerical limits. The 7% per-country cap primarily affects foreign nationals from
countries that send relatively large numbers of immigrants to the United States (e.g., Mexico,
China, India, Philippines). As a result, many foreign nationals who meet the U.S. immigrant
qualifications, and whose immigrant petitions USCIS has approved, must wait years before a
numerical y limited visa (or LPR slot) from DOS becomes available. As of November 1, 2020,
the queue of approved family-sponsored immigrants waiting for LPR status numbered 3.8 mil ion
persons.15 As of November 16, 2020, the queue of approved employment-sponsored immigrants
waiting for LPR status numbered roughly 1 mil ion persons.16
Diversity Immigrant Visa
The diversity immigrant visa fosters legal immigration from countries that send relatively few
immigrants to the United States.17 Each year, 55,000 visas are made available to selected natives
of countries from which immigrant admissions totaled less than 50,000 over the preceding five
years. Since the visa’s inception in the early 1990s, the regional distribution of diversity lottery
immigrants has shifted from Western European to African and Eastern European countries.18
To be eligible for a diversity immigrant visa, foreign nationals must have a high school education
or two years of work experience within the past five years in an occupation that requires at least
two years of training or experience to perform. Diversity immigrant visa applicants are selected
by lottery. Those selected from the diversity immigrant visa lottery must also meet the standard
eligibility criteria required for most immigrants before they are al owed entry into the United
States.
Refugees and Asylees
The United States has long held to the principle that it wil not return a foreign national to a
country where his/her life or freedom would be threatened. This is embodied in several INA
provisions, notably in those defining refugees and asylees. A refugee is a person who is unable or
unwil ing to return to their home country or country of residence because of persecution, or a
wel -founded fear of persecution, on account of five possible criteria: (1) race, (2) religion, (3)
nationality, (4) membership in a particular social group, or (5) political opinion.19 An asylee is a
person who meets the definition of a refugee in terms of persecution or a wel -founded fear of
persecution but who is present in the United States or at a land border or port of entry to the
United States.

15 U.S. Department of State, National Visa Center, Annual Report of Immigrant Visa Applicants in the Family-
sponsored and Em ploym ent-based preferences Registered at the National Visa Center as of Novem ber 1, 20 20
. For
more discussion of the visa queue, see CRS Report R43145, U.S. Fam ily-Based Im migration Policy.
16 U.S. Citizenship and Immigration Services, “ Form I 140, I 360, I 526 Approved Employment Based Petitions
Awaiting Visa Availability by Preference Category and Country of Birth As of November 16, 2020.” For background
information on how this queue is computed, see archived CRS Report R45447, Perm anent Em ployment-Based
Im m igration and the Per-country Ceiling
.
17 For more information, see CRS Report R45973, The Diversity Immigrant Visa Program .
18 For more information, see CRS Report R45102, Diversity Immigrants’ Regions and Countries of Origin: Fact Sheet.
19 While persons seeking refugee status often reside in a second country that is neither their home country nor the
United States, some reside in their home countries in certain circumstances. See 8 U.S.C. §1101)(a)(42)(B).
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Refugee status is granted within numerical limits. Refugee admissions differ from other
immigrant admissions because their annual number, known as the refugee ceiling, and their
al ocation are not mandated in statute but set each year by the President, in consultation with
Congress. Between FY2000 and FY2019, the annual refugee ceiling number of U.S. refugees
admitted averaged 55,934, with a low of 22,544 (in FY2018) and a high of 84,994 (in FY2016).20
The variation in refugee admissions is largely due to variation in the refugee ceilings set during
this time. Annual refugee admissions are typical y lower than permitted by the annual refugee
ceiling because of delays from processing and screening.
For FY2021, the worldwide refugee ceiling was set at 15,000, the lowest in the 40-year history of
the U.S. Refugee Admissions Program. In contrast with prior years’ regional al ocations, refugee
al ocations in FY2021 were made by “population of special humanitarian concern.” These
populations included refugees facing persecution on religious grounds (5,000); refugees from Iraq
(4,000); refugees from El Salvador, Guatemala, or Honduras (1,000); and refugees in other
specified groups (5,000).21
In 2021, the Biden Administration issued two emergency determinations that changed the
al ocation process back to a regional al ocation and increased the FY2021 refugee ceiling to
62,500. The regional al ocations are as follows: Africa (22,000), East Asia (6,000), Europe and
Central Asia (4,000), Latin America and the Caribbean (5,000), Near East and South Asia
(13,000), and an unal ocated reserve (12,500).22
Asylum is not numerical y limited. A foreign national in the United States may affirmatively
apply to USCIS for asylum or may defensively seek asylum before an immigration judge during
proceedings that determine an individual’s removability under the INA.23 Typical y, foreign
nationals arriving at a U.S. port of entry who lack proper immigration documents for admission
or who engage in fraud or misrepresentation are placed in expedited removal (see “Removal”).
However, if they express a fear of persecution, they receive a credible fear review by a USCIS
asylum officer and—if found to have credible fear—are placed in standard removal proceedings
and referred to an immigration judge for a hearing on their asylum claims.24
Other Pathways to Lawful Permanent Resident Status
In addition to the primary components of permanent immigration discussed above, the INA
contains several other pathways to LPR status, though they account for relatively few immigrants
each year. The most prominent among these are cancellation of removal, U nonimmigrant visas,
and T nonimmigrant status.25

20 See U.S. Department of State, Bureau of Population, Refugees and Migration, Office of Admissions – Refugee
Processing Center, “ Summary of Refugee Admissions as of 30-April-2021.” For additional information, see CRS
Report RL31269, Refugee Adm issions and Resettlem ent Policy.
21 T he White House, “Presidential Determination on Refugee Admissions for Fiscal Year 2021,” 85 Federal Register
71219-71221, November 6, 2020. According to DOS’s Refugee Processing Center, 11,814 refugees were admitted in
FY2020, and 2,334 have been admitted in FY2021 as of April 30, 2021. Ibid.
22 Executive Office of the President, “Emergency Presidential Determination on Refugee Admissions for Fiscal Year
2021,” 86 Federal Register 21159-21160, April 22, 2021; and Executive Office of the President, “Emergency Presidential
Determination on Refugee Admissions for Fiscal Year 2021,” 86 Federal Register 24475-24476, May 7, 2021.
23 For more information, see CRS Report R45539, Immigration: U.S. Asylum Policy.
24 INA §235(b) defines credible fear as a significant possibility, taking into account the credibility of the statements
made by the alien and other facts known to the officer, that the alien could establish eligibility for asylum.
25 For a detailed and complete list of categories of foreign nat ionals receiving LPR status, see DHS Office of
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Cancellation of removal is a discretionary form of relief granted by an immigration judge to
aliens in removal proceedings. To receive it, a foreign national must demonstrate substantial ties
to the United States, be of good moral character, and not have been convicted of a crime that
makes him/her removable. Requirements differ by legal status, with nonpermanent residents
facing more stringent requisites than permanent residents.26 Because an immigration judge grants
cancel ation of removal at his/her discretion, no fixed standard exists for who merits relief. The
foreign national must show that he/she is eligible for and deserves the relief. Grants of
cancel ation of removal are limited to 4,000 LPRs and 4,000 nonpermanent residents per year.27
U nonimmigrant visas are granted to certain victims who help law enforcement agencies
investigate and prosecute domestic violence, sexual assault, human trafficking, and other crimes.
To qualify for U status, a foreign national must file a petition and establish that he/she (1)
suffered substantial physical or mental abuse as a result of having been a victim of qualifying
crimes that violated the laws of the United States or occurred in the United States; (2) possesses
information about the criminal activity involved as certified by a law enforcement or immigration
official; and (3) has been, is being, or is likely to be helpful in the investigation and prosecution
of the crime(s) by federal, state, or local law enforcement authorities. U visa recipients, as wel as
their immediate family members, can acquire LPR status. The INA limits U visas to 10,000
principal applicants annual y.28
T nonimmigrant status is granted to victims of severe forms of human trafficking.29 T status
recipients may remain in the United States for four years and apply for LPR status after three. To
qualify for T status, trafficking victims must (1) demonstrate that they are victims of a severe
form of trafficking in persons; (2) be physical y present in the United States, its territories, or a
U.S. port of entry either because of such trafficking or because they wil participate in related
investigations or prosecutions; (3) have complied with requests to assist law enforcement
investigating or prosecuting trafficking acts; and (4) be likely to suffer unusual and severe harm
upon removal. Such aliens must also be admissible to the United States or obtain a waiver of
inadmissibility (see “Visa Issuance and Security”). The INA limits T status to 5,000 principal
applicants annual y.
Temporary Immigration
Each year, the United States admits mil ions of nonimmigrants, such as tourists, foreign students,
diplomats, temporary workers, exchange visitors, international y known entertainers,
intracompany business personnel, and crew members on foreign vessels. DOS issues specific
types of nonimmigrant visas within 24 major nonimmigrant visa categories. Categories are often
referred to by the letter and numeral denoting the related subsection within INA Section 101(a)
(e.g., B-2 tourists, F-1 foreign students, H-2A temporary agricultural workers).30

Immigration Statistics, 2019 Yearbook of Im m igration Statistics, T able 7.
26 For example, nonimmigrants and unauthorized aliens who seek cancelation of removal must establish that removal
would result in “exceptional and extremely unusual hardship” to the alien’s citizen or LPR spouse, parent, or child.
T hat same standard does not apply to immigrants (LPRs).
27 For more information, see CRS Report R43892, Alien Removals and Returns: Overview and Trends.
28 T here is no limit for family members who derive U status or T status from the principal applicant, such as spouses,
children, or other eligible family members. For more information, see CRS Report R46584, Im migration Relief for
Victim s of Trafficking
.
29 For more information, see CRS Report R46584, Immigration Relief for Victims of Trafficking.
30 For more information, see CRS Report R45040, Immigration: Nonimmigrant (Temporary) Admissions to the United
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Requirements for Temporary Admission
Foreign nationals who apply for temporary admission must demonstrate, both to DOS consular
officers at the time they apply for a visa in their home countries, as wel as to CBP officers when
they apply for admission upon arrival in the United States, that they are eligible for both
nonimmigrant status general y and the specific requested nonimmigrant visa. In addition, because
the INA presumes that al aliens seeking admission to the United States are coming to live
permanently, nonimmigrant applicants must demonstrate that they intend to stay for a temporary
period and a specific purpose (see “Visa Issuance and Security”).31 With certain exceptions,
nonimmigrants are prohibited from working in the United States.
In recent years, the largest nonimmigrant groups entering the United States have included B-1
business visitors and B-2 tourists (temporary visitors for business or pleasure), Border Crossing
Card holders, L intracompany transferees employed with international firms,32 H-1B professional
specialty workers,33 H-2A agricultural guest workers and H-2B nonagricultural guest workers,34 J
cultural exchange visitors (including professors, students, foreign medical graduates, teachers,
resort workers, camp counselors, and au pairs), and F foreign students. In FY2019, for example,
DOS consular officers issued 8.7 mil ion nonimmigrant visas, down from a peak of 10.9 mil ion
in FY2015. There were approximately 6.5 mil ion tourism and business visas, which comprised
about three-quarters of al nonimmigrant visas issued in FY2019. Other notable groups were
temporary workers (963,000 or 11.0%), cultural exchange visitors (392,000 or 4.5%), and
students (389,000 or 4.4%).35
Border Crossing Card
Border crossing cards (BCC) al ow Mexican citizens who live in Mexico and are admissible as B-
1 business or B-2 tourist visitors to briefly enter the United States. In FY2020, DOS issued
662,536 border crossing cards to Mexican nationals.36 The BCC may be used for multiple entries
and is usual y valid for 10 years. Current rules limit BCC holders to visits of up to 30 days within
a zone of 25 miles along the border in Texas and California, 55 miles along the New Mexico
border, and 75 miles along the Arizona border.37 U.S. admissions from persons possessing border
crossing cards in FY2019 totaled 104.6 mil ion.38

States.
31 Many temporary visa holders ultimately are able to adjust their status to LPR status after they have been admitted to
the United States as nonimmigrants. In FY2019, for example, of the 1,031,765 foreign nationals who were granted
lawful permanent resident status, 459,252 (44%) were new arrivals from abroad and 572,513 (56%) adjusted status
from a nonimmigrant status while residing in the United States. Data to show the nonimmigrant categories that foreign
nationals adjust status from are unavailable. See DHS 2019 Yearbook of Im m igration Statistics, T able 6.
32 For more background, see archived CRS Report RL32030, Immigration Policy for Intracompany Transfers (L Visa):
Issues and Legislation
.
33 For more information, see archived CRS Report R43735, Temporary Professional, Managerial, and Skilled Foreign
Workers: Policy and Trends
.
34 For more information, see CRS Report R44849, H-2A and H-2B Temporary Worker Visas: Policy and Related
Issues
.
35 For statistics on nonimmigrant visas by category, see U.S. Department of State, Bureau of Consular Affairs, Report
of the Visa Office
2020.
36 U.S. Department of State, Bureau of Consular Affairs, Report of the Visa Office 2020, T able XVI.
37 8 C.F.R. §212.6.
38 See DHS, 2019 Yearbook of Immigration Statistics, T able 25. BCC admissions are computed by subtracting “T otal I-
94 admissions” from “ T otal all admissions” in T able 25. Admissions are events, not unique individuals.
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Visa Issuance and Security
In general, nonresident foreign nationals who wish to come to the United States, whether
permanently or temporarily, must obtain a visa.39 A visa permits a foreign national to travel to a
U.S. port of entry and request permission from CBP to enter the country. To obtain a visa, foreign
nationals must establish their qualification for a specific visa under its admission criteria. In
addition, visa issuances can be denied under three main INA provisions:
 insufficient information under INA Section 221(g);
 the grounds of inadmissibility under INA Section 212(a); and
 for nonimmigrant applicants, the presumption of seeking permanent residence
under INA Section 214(b).
Immigration applications and petitions almost al require fees.40 For example, a U.S. citizen
wishing to sponsor his/her foreign-born spouse as an immediate relative must pay $535 when
submitting a petition that establishes the familial relationship (USCIS Form I-130).41 If the spouse
is living in the United States on a temporary nonimmigrant visa, the spouse must pay an
additional $1,225 to apply to adjust to permanent resident status (USCIS Form I-485).42 If the
spouse resides abroad, he/she must pay a $325 DOS processing fee43 and a $220 USCIS
immigrant fee.44 As such, fees can represent a substantial financial outlay in some cases.
The application must be complete.45 A visa denial under INA Section 221(g) indicates that the
DOS consular officer abroad lacks sufficient information to determine if a foreign national is
eligible to receive a visa. A consular officer may also disqualify a visa applicant if (1) he/she
knows or has reason to believe that the alien is inadmissible under INA Section 212(a) (described
below) or any other provision of law, or (2) the application fails to comply with INA provisions or
regulations.
Al foreign nationals must undergo admissibility reviews. Consular officers must decide whether
a foreign national is excludable under the grounds in INA Section 212(a), which include the
following:
 health-related grounds,
 criminal grounds,46
 security and terrorist concerns,

39 Exceptions to this rule include citizens or nationals of the (currently) 39 Visa Waiver Program (VWP) designated
countries, Mexican and Canadian NAFT A Profession al Workers, and citizens of Canada and Bermuda. For more
information, see CRS Report RL32221, Visa Waiver Program ; and U.S. Department of State, “ Travel Without A
Visa,” https://travel.state.gov/content/travel/en/us-visas/tourism-visit/travel-without-a-visa.html.
40 USCIS, which processes and adjudicates most immigration-related applications and petitions, operates largely on fee
revenue. A fee schedule for all applications and petitions can be found at https://www.uscis.gov/g-1055. For
background information, see archived CRS Report R44038, U.S. Citizenship and Im m igration Services (USCIS)
Functions and Funding
.
41 U.S. Citizenship and Immigration Services, “USCIS Immigrant Fee,” https://my.uscis.gov/uscis-immigrant-fee/.
42 Ibid.
43 Ibid.
44 Ibid.
45 Other costs may include legal fees, translation services fees, medical examination costs, fees related to the issuance
of any required official documents, and travel expenses.
46 For more information, see CRS Report R45151, Immigration Consequences of Criminal Activity.
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 public charge risk (e.g., indigence),47
 seeking to work without proper labor certification,48
 previous il egal U.S. entry and U.S. immigration law violations,49
 ineligibility for U.S. citizenship, and
 having been previously removed from the United States.
The INA describes procedures for making and reviewing an inadmissibility determination and
specifies conditions under which some of these provisions may be waived. A visa denial under
INA Section 214(b) indicates that the foreign national was unable to demonstrate to the consular
officer that he/she had sufficient ties to his/her home country to return home.50 This is the most
common reason that DOS denies nonimmigrant visas.
In FY2019, 462,422 foreign nationals were issued immigrant visas, and 298,017 immigrant visa
applications were initial y denied based on ineligibility findings (177,902 of which were
ultimately overcome). In the same fiscal year, 8,742,068 foreign nationals were issued
nonimmigrant visas, and 3,742,074 nonimmigrant applications were initial y denied based on
ineligibility findings (830,177 of which were overcome).51
Al visa applicants are required to submit their photographs, fingerprints, and biographic and
demographic information. Visa applicants are checked against multiple databases and information
sources for security purposes. Al prospective LPRs and certain prospective nonimmigrants must
also submit to physical and mental examinations. Visa applicants general y must be interviewed
by a consular officer to determine whether they are qualified to receive a visa. Consular officers’
decisions on whether or not to grant foreign nationals a visa are not subject to judicial appeals.
Visa applicants who were denied a visa for a particular ineligibility, and who meet certain
conditions, may apply to DHS for a waiver of that ineligibility.
Visa Waiver Program
The Visa Waiver Program (VWP) al ows most citizens or nationals from participating countries to
enter the United States as temporary visitors for business or pleasure without obtaining visas from
U.S. consulates abroad. Those entering the country under the VWP undergo a biographic (e.g.,
name, address, date of birth) rather than a biometric (e.g., fingerprint) security screening and do

47 For more information, see CRS In Focus IF11467, Immigration: Public Charge; and CRS Legal Sidebar LSB10341,
DHS Final Rule on Public Charge: Overview and Considerations for Congress.
48 For more information, see archived CRS Report RL33977, Immigration of Foreign Workers: Labor Market Tests
and Protections
.
49 Unauthorized aliens who were present illegally in the United States for between 6 and 12 months are barred from
readmission to the United States for 3 years, and those present for more than 1 year are barred for 10 years (the “ 3 - and
10-year bars”). INA §212(a)(9)(B).
50 Some nonimmigrant visas, including H-1 professional workers, L intracompany transfers, K fiancé visas, and V
accom panying family m em bers
allow visa holders to simultaneously seek LPR status. T he same is true for beneficiaries
of T and U nonimmigrant status (for victims of human trafficking and crime, respectively). Nonimmigrants seeking one
of these visas or statuses do not need to prove t hey are not coming to reside permanently in the United States.
51 Note that applications refused does not necessarily equal the number of foreign nationals refused because an
applicant can apply for a visa and be found ineligible more than once within the same fiscal year. Note also that a visa
application may be denied in one fiscal year and overcome in a subsequent fiscal year. U.S. Department of State,
Annual Report of the Visa Office 2019, T ables XV, XVI(B), and XX.
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not need to be interviewed by a U.S. government official before their trip.52 In FY2019, roughly
19.7 mil ion pleasure and 3.2 mil ion business visitors entered the United States using the VWP.53
Types of “Quasi-legal” Status
Two immigration mechanisms that al ow persons to remain legal y in the United States without
being legal y admitted into the country, Temporary Protected Status and parole, are described
below. Other options that al ow persons to remain legal y in the United States without being
legal y admitted, including Deferred Enforced Departure, withholding of removal, and deferred
action, are described in later sections of this report.
Temporary Protected Status
When extraordinary conditions such as civil unrest, violence, or natural disasters occur in foreign
countries, foreign nationals from those places who are present in the United States may not be
able to return home safely. The INA al ows DHS, in consultation w ith DOS, to grant Temporary
Protected Status (TPS) to such foreign nationals, provided that doing so is consistent with U.S.
national interests.54 Congress has also provided TPS legislatively.
While TPS beneficiaries may obtain employment authorization, TPS does not provide a path to
LPR status. DHS can designate TPS for 6 to 18 months and may extend it if conditions do not
change in the designated country. Based on the most recent designations for each country, there
are an estimated 320,000 TPS recipients from 10 countries: El Salvador, Haiti, Honduras, Nepal,
Nicaragua, Somalia, South Sudan, Sudan, Syria, and Yemen.55 In March 2021, the Biden
Administration designated three more countries for TPS: Venezuela, Burma, and Haiti. An
estimated 323,000 Venezuelans, 1,600 Burmese, and 100,000-150,000 Haitian nationals could be
eligible to apply for TPS under these designations. The Trump Administration terminated TPS for
six countries—El Salvador, Haiti, Honduras, Nepal, Nicaragua, and Sudan—but these
terminations have not taken effect due to litigation. Certain Liberians and Venezuelans currently
maintain relief under a similar administrative mechanism known as Deferred Enforced Departure
(DED).
Parole
DHS may parole an alien into the United States for urgent humanitarian reasons or significant
public benefit at its discretion and on a case-by-case basis. Parole is granted for a specified period
and does not constitute formal admission to the United States. Parolees may obtain employment
authorization but must depart the United States when the parole expires or, if eligible, be admitted
in a lawful status. Parolees may also apply for re-parole.56

52 For more information, see CRS Report RL32221, Visa Waiver Program .
53 See DHS, 2019 Yearbook of Immigration Statistics, T able 25.
54 INA §244, 8 U.S.C. §1254a. For more information, see CRS Report RS20844, Temporary Protected Status and
Deferred Enforced Departure
.
55 Figures for estimated T PS holders from individual countries come from Federal Register announcements. For more
information on T PS countries, see https://www.uscis.gov/humanitarian/temporary-protected-status.
56 For more information, see CRS Report R46570, Immigration Parole.
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Naturalization
Under U.S. immigration law, al LPRs may become U.S. citizens through a process known as
naturalization. With some exceptions, naturalization requirements include the following:
 residing continuously in the United States as LPRs for five years;
 demonstrating possession of good moral character;
 demonstrating basic English skil s and knowledge of U.S. history and civics; and
 taking an oath of al egience to the United States.57
Annual naturalizations averaged 717,195 between FY2010 and FY2019, with 843,593 foreign
nationals naturalizing in FY2019.58 In 2019, census data indicate that an estimated 23.2 mil ion
naturalized citizens resided in the United States, comprising 52% of the estimated 44.9 mil ion
foreign-born U.S. residents.59
Immigration Enforcement
Immigration enforcement involves the identification, investigation, apprehension, detention,
prosecution, and deportation (removal) of foreign nationals who are inadmissible and/or violate
U.S. laws and become removable. Immigration enforcement encompasses enforcement of the
INA’s civil provisions (e.g., violations of admission requirements) as wel as its criminal
provisions (e.g., improper entry, marriage fraud, alien smuggling). CBP is responsible for border
security where foreign nationals enter at U.S. land, air, and sea ports of entry (POEs) and along
U.S. borders between POEs. ICE is responsible for enforcing immigration laws in the U.S.
interior, including worksite enforcement.60
Border Security at Ports of Entry
Foreign nationals arrive in the United States at any of the 329 land, air, and sea POEs. They are
met by CBP officers whose primary immigration enforcement mission is to ensure that such
travelers are eligible to enter the United States and to exclude inadmissible foreign nationals.
Possession of a visa by a foreign national does not guarantee U.S. admission if a CBP officer
finds the individual inadmissible under the law.61
In FY2019, about 410 mil ion travelers (U.S. citizens and noncitizens) entered the United States,
including roughly 249 mil ion land travelers, 136 mil ion air passengers and crew, and 26 mil ion

57 For more information, see CRS Report R43366, U.S. Naturalization Policy; and CRS In Focus IF10884, Expedited
Citizenship through Military Service
.
58 U.S. Department of Homeland Security, Yearbook of Immigration Statistics 2019, T able 20.
59 U.S. Census Bureau, 2019 American Community Survey data, 1-year estimates, accessed by CRS on January 5,
2021, at United States Census Bureau, “ Explore Census Data,” https://data.census.gov/cedsci/. Noncitizens include
LPRs, lawful temporary nonresidents, and unauthorized aliens. DHS has estimated that 9.2 million of the estimated
13.6 million LPRs residing in the United States in 2019 were eligible to naturalize based on their length of time living
in the country. See Bryan Baker, Estim ates of the Lawful Perm anent Resident Population in the United States and the
Subpopulation Eligible to Naturalize: 2015-2019
, DHS Office of Immigration Statistics, September 2019.
60 T his report does not cover immigration enforcement along U.S. coastal waters which the U.S. Coast Guard, Alien
Migrant Interdiction Operations, oversees. For more information, see https://www.gocoastguard.com/about -the-coast -
guard/discover-our-roles-missions/migrant -interdiction.
61 INA 221(h), 8 U.S.C. §1201(h).
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sea passengers and crew. During the same period, about 288,000 aliens were denied admission
and 13,000 aliens were arrested on criminal warrants.62
CBP has the dual responsibility for facilitating the flow of lawful travelers, immigrants, and trade
while providing security at and between POEs against inadmissible persons and contraband.63
This includes screening at multiple points in the immigration process, beginning wel before
travelers arrive at U.S. POEs. DHS and other departments involved in the inspection process use
screening tools to distinguish known, low-risk travelers who may be eligible for expedited
admissions processing from lesser-known, higher-risk travelers who are usual y subject to more
extensive secondary inspections.64
DHS is responsible for implementing an electronic entry-exit system at POEs, a task Congress
mandated in 1996. While CBP collects a portion of the requisite biographic and biometric data
from noncitizens at various stages of their entry to and exit from the United States, the
Government Accountability Office (GAO) reports that implementation of a fully automated
biometric system has proven chal enging. DHS has fully implemented the biometric entry system
at al U.S. ports of entry. Reportedly, the biometric exit system currently captures information on
about 60% of foreign nationals aged 14-79 departing the United States via commercial air
carriers. Other technologies are gradual y being employed at air, sea, and land POEs.65
Border Security Between Ports of Entry
Border security between POEs protects against unauthorized land border entry into the United
States, which has been a concern for Congress since the 1970s, when unauthorized migration first
registered as a major national issue. Border security has received greater attention since the
terrorist attacks on September 11, 2001.
CBP’s unauthorized migration control strategy between POEs strives for operational control,
which the agency describes as “the ability to perceive and comprehend the operating environment
(situational awareness), mobilize assets, infrastructure and barriers to prevent criminal activity
(impedance and denial), and respond to and resolve any il icit cross-border incursions (response
and resolution).”66 Impedance and denial, in particular, involve investments in physical
infrastructure described below. They also encompass “enforcement with consequences,” which
includes making migrants who commit crimes face criminal charges and incur penalties
(including incarceration) prior to removal.
CBP’s border security strategies and investments include the construction and maintenance of
tactical infrastructure, instal ation and monitoring of surveil ance technology, and the deployment
of U.S. Border Patrol agents to prevent unlawful entries of people and contraband into the United
States (e.g., unauthorized migrants, terrorists, firearms, narcotics). Tactical infrastructure includes

62 U.S. Department of Homeland Security, U.S. Customs and Border Protection, “CBP Enforcement Statistics Fiscal
Year 2021,” https://www.cbp.gov/newsroom/stats/cbp-enforcement -statistics (for admission denied and arrest figures);
U.S. Customs and Border Protection, “On a T ypical Day in Fiscal Year 2019, CBP…,” https://www.cbp.gov/
newsroom/stats/typical-day-fy2019 (for all other figures). Annual figures in text are derived by multiplying daily
figures in the CBP source by 365. FY2020 statistics are available, but are not presented because the COVID -19
pandemic significantly limited international travel in that year.
63 For more information, see CRS Report R43356, Border Security: Immigration Inspections at Ports of Entry.
64 For more information, see CRS Report R46783, Trusted Traveler Programs.
65 For more information, see CRS In Focus IF11634, Biometric Entry-Exit System: Legislative History and Status.
66 U.S. Customs and Border Protection, 2020 U.S. Border Patrol Strategy, August 2019; and U.S. Customs and Border
Protection Strategy 2021-2026
, publication 1280-1220, December 2020.
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physical barriers between POEs which vary by age, purpose, form, and location. Since receiving
authorization from Congress in 1996, DHS has built 653 miles of several types of barriers along
the U.S.-Mexico border, which spans nearly 2,000 miles.67 Tactical infrastructure also includes
roads, gates, bridges, and lighting designed to support border enforcement and disrupt and impede
il icit activity. Surveil ance technology assists CBP in the detection, identification, and
apprehension of individuals il egal y entering the United States between POEs. Ground
technology includes sensors, cameras, and radar tailored to fit specific terrain and population
densities. Manned and unmanned aerial and marine surveil ance vessels patrol regions
inaccessible by motor vehicle.68 In FY2019, 19,648 U.S. Border Patrol agents were stationed
nationwide, with most (17,731) at the Southwest border.69
Apprehensions of unauthorized migrants, a widely cited border security metric, are positively
related to unauthorized migrant flows.70 Annual apprehensions were relatively low in the 1960s,
climbed sharply after 1965, and reached peaks of roughly 1.7 mil ion in both 1986 and 2000.
Since 2000, apprehensions general y declined, with some fluctuations, to a 46-year low of
310,531 in FY2017.71 Apprehension levels subsequently increased to 859,501 in FY2019 before
declining to 405,036 in FY2020. They have since increased to 898,949 in the first eight months of
FY2021.72
In March 2020, CBP curtailed its processing of those not considered essential travelers due to the
global COVID-19 pandemic. Those affected included mostly asylum seekers arriving at the
Southwest border. Under a public health order (referred to as Title 42) that was issued by the U.S.
Department of Health and Human Services’ Centers for Disease Control and Prevention, CBP
expel ed most migrants back to Mexico or in some cases their home countries.73 As of the cover
date of this report, Title 42 was stil in effect for single adult migrants and some migrant families.
In past years, debates centered on how much immigration enforcement affected migrant flows
compared with other factors like the U.S. unemployment rate.74 More recently, some
commentators have cited both anticipation and enactment of more or less restrictive policies by

67 For more information, see CRS Report R45888, DHS Border Barrier Funding; and CRS Insight IN11193, Funding
U.S.-Mexico Border Barrier Construction: Current Issues
.
68 See archived CRS Insight IN11040, Border Security Between Ports of Entry: Homeland Security Issues in the 116th
Congress
.
69 U.S. Customs and Border Protection, U.S. Border Patrol Fiscal Year Staffing Statistics (FY 1992 - FY 2019),
accessed June 7, 2021, https://www.cbp.gov/sites/default/files/assets/documents/2020-Jan/
U.S.%20Border%20Patrol%20Fiscal%20Year%20Staffing%20Statistics%20%28FY%201992%20 -
%20FY%202019%29_0.pdf.
70 See for example, T homas J. Espenshade, “ Using INS Border Apprehension Data to Measure the Flow of
Undocumented Migrants Crossing the U.S.-Mexico Frontier,” International Migration Review, vol. 29 (Summer 1995),
pp. 545-565. For more on border security metrics, see archived CRS Report R44386, Border Security Metrics Between
Ports of Entry
. Apprehension figures include those at the northern, southern and coastal borders. See also U.S.
Department of Homeland Security, Border Security Metrics Report, August 5, 2020.
71 U.S. Customs and Border Protection, “Stats and Summaries,” Nationwide Illegal Alien Apprehensions, Fiscal Years
1925-2019
, at https://www.cbp.gov/newsroom/media-resources/stats.
72 U.S. Customs and Border Protection, “CBP Enforcement Statistics Fiscal Year 2021,” at https://www.cbp.gov/
newsroom/stats/cbp-enforcement-statistics. In March, 2020, apprehension statistics were expanded to include
expulsions under T itle 42 (Public Health) of the U.S. code. T he CBP currently reports statistic s for encounters which
include both T itle 8 apprehensions and T itle 42 expulsions.
73 CRS Report R46755, The Law of Asylum Procedure at the Border: Statutes and Agency Implementation.
74 For more information, see archived CRS Report R42138, Border Security: Immigration Enforcement Between Ports
of Entry
.
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the Trump and Biden Administrations, respectively, as an additional cause of fluctuations in
apprehension levels.75
Detention
The INA authorizes—and in some cases requires—DHS to detain foreign nationals who are
subject to removal from the United States. Detention rules are multifaceted and depend on several
factors, such as whether the individual is seeking admission or has been lawfully admitted into
the country, has engaged in certain proscribed conduct, and has been issued a final order of
removal. Four INA provisions provide a framework for immigration detention:
 INA Section 236(a) general y authorizes the detention of aliens pending a
decision on whether the alien is to be removed from the United States and
permits those who are not subject to mandatory detention to be released on bond
or their own recognizance;
 INA Section 236(c) general y requires the detention of aliens who are removable
because of specified criminal activity or terrorism-related grounds;
 INA Section 235(b) general y requires the detention of applicants for admission
who appear subject to removal, including aliens arriving at a POE and certain
other aliens who have not been admitted or paroled into the United States; and
 INA Section 241(a) general y requires an alien subject to a final order of removal
to be held during the 90-day period when the alien’s removal is effectuated. DHS
may detain an alien beyond 90 days if the agency cannot effectuate removal and
the alien fal s within certain categories.76
DHS detained 510,854 aliens during FY2019.77 The amount of detention space is controlled
largely through congressional appropriations.
ICE must obtain travel documents to repatriate removable foreign nationals. Because some
countries refuse to provide travel documents or delay doing so, ICE has regularly released
sizeable numbers of detainees following their full detention term, including criminal aliens—an
outcome that has been criticized by some Members of Congress.78 The U.S. Supreme Court has
ruled that foreign nationals who are subject to a final removal order and are facing indefinite
detention pending DHS’s efforts to secure their removal general y may not be detained for more
than six months.79

75 For more information, see CRS Report R46012, Immigration: Recent Apprehension Trends at the U.S. Southwest
Border
and CRS Report R45489, Recent Migration to the United States from Central Am erica: Frequently Asked
Questions
.
76 For more information on standards and criteria for making detention decisions, see CRS In Focus IF11343, The Law
of Im m igration Detention: A Brief Introduction
; and CRS Report R45915, Im m igration Detention: A Legal Overview.
77 U.S. Department of Homeland Security, Office of Immigration Statistics, Annual Flow Report, Immigration
Enforcem ent Actions: 2019
, T able 5, September 2020.
78 U.S. Congress, House Committee on the Judiciary, Oversight of United States Immigration and Customs
Enforcem ent
, opening statement of the Honorable Bob Goodlatte, Chairman , 114th Cong., 2nd sess., September 22,
2016. For more information, see CRS In Focus IF11343, The Law of Im m igration Detention: A Brief Introduction ; and
archived CRS Report RL32369, Im migration-Related Detention.
79 Zadvydas v. Davis, 533 U.S. 678, 693 (2001).
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Removal
Removing foreign nationals who violate U.S. immigration and other laws is central to
immigration enforcement, and the INA provides broad authority to DHS and DOJ to remove
certain foreign nationals from the country. These persons include unauthorized aliens as wel as
lawfully present foreign nationals who commit certain acts that make them removable. Any
foreign national found to be inadmissible (either before or after U.S. entry) or deportable under
grounds specified in the INA may be ordered removed.
To remove a foreign national who has already been lawfully admitted, the U.S. government must
prove that the individual has violated one of the grounds of deportation specified in INA Section
237(a):
 being inadmissible at the time of entry80 or violating one’s immigration status;
 committing certain criminal offenses, including crimes of “moral turpitude,”
aggravated felonies, alien smuggling, and high-speed flight from an immigration
checkpoint;81
 failing to register with DHS (if required) or committing document fraud;
 being a security risk (including violating any law relating to espionage, engaging
in criminal activity that endangers public safety, partaking in terrorist activities,
or assisting in Nazi persecution or genocide);
 becoming a public charge within five years of entry; or
 voting unlawfully.
The INA describes procedures for making and reviewing a removability determination, and
specifies conditions under which certain grounds of removal may be waived. DHS officials may
exercise some discretion in pursuing removal orders, and certain removable aliens may be eligible
for permanent or temporary relief from removal. Other grounds for removal (e.g., some criminal
offenses, terrorist activities) may render foreign nationals ineligible for most forms of relief and
may make them subject to a more streamlined removal process, both at the U.S. border and
within the U.S. interior.
Under the standard removal process, an immigration judge from EOIR determines in a civil
proceeding whether a foreign national is removable. The immigration judge may grant certain
forms of relief (e.g., asylum, cancel ation of removal), and removal decisions are subject to
administrative and judicial review.
Under streamlined removal procedures, including expedited removal and reinstatement of
removal (i.e., when DHS reinstates a removal order for a previously removed individual),
opportunities for relief and review are general y limited. Under expedited removal (INA §235(b)),
an alien who is inadmissible because he/she lacks proper documentation or has committed fraud
or wil ful misrepresentation to gain U.S. admission may be removed without any further hearings
or review, unless he/she indicates an intention to apply for asylum.

80 Grounds of inadmissibility are outlined in INA Section 212, 8 U.S.C. Section 182. If individuals are removed
because they were inadmissible at the time of entry, they are removed under INA Section 212, not INA Section 237.
81 Crimes of moral turpitude are determined by case law. For more information, see CRS Report R45151, Immigration
Consequences of Crim inal Activity
.
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Two options that are often referred to as returns—voluntary departure and withdrawal of petition
for admission
—require foreign nationals to leave the United States promptly but exempt them
from certain penalties associated with removal.
Fol owing an order of removal, a foreign national is general y ineligible to return to the United
States for a minimum of five years and possibly longer depending on the reason for and type of
removal. Absent other factors, unlawful presence in the United States is a civil violation, not a
criminal offense, and removal and its associated administrative processes are civil proceedings.
As such, persons in removal proceedings general y have no right to government-provided
counsel, although they may obtain counsel at their own expense.82
Programs Targeting Criminal Aliens
Although al unauthorized aliens are potential y subject to removal, the removal of criminal aliens
(noncitizens who have been convicted of a crime in the United States) has been a statutory
priority since 1986.83 Programs targeting criminal aliens for removal have grown substantial y
since DHS was established in 2002.
ICE currently operates several programs to identify and remove criminal and other removable
aliens, including the Criminal Alien Program (CAP), an umbrel a program for coordinating the
agency’s resources.84 CAP includes a data sharing infrastructure, or interoperability, between
DHS and DOJ that screens for both immigration and criminal violations when individuals are
booked into jail. To pursue known at-large criminal aliens and fugitive aliens outside of
controlled settings (i.e., administrative offices or custodial settings), ICE uses the National
Fugitive Operations Program
(NFOP). In addition to programs using DHS personnel, ICE’s
Section 287(g) program al ows DHS to delegate certain immigration enforcement functions to
special y trained state and local law enforcement officers, under federal supervision.85
Options for Aliens in Removal Proceedings
INA provisions permit certain removable aliens to remain in the United States, either permanently
or temporarily.86 Options that provide permanent relief by conferring or leading to lawful
permanent resident status include cancel ation of removal (discussed above) and defensive
asylum applied for during removal proceedings.87 Options that provide temporary relief include

82 For more information, see CRS In Focus IF11357, Expedited Removal of Aliens: An Introduction; CRS Legal
Sidebar LSB10150, Im m igration Laws Regulating the Adm ission and Exclusion of Aliens at the Border; and CRS
Report R43892, Alien Rem ovals and Returns: Overview and Trends.
83 T he Immigration Reform and Control Act (P.L. 99-603) made deporting aliens who had been convicted of certain
crimes a formal enforcement priority. T he law 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.”
84 For more information, see CRS Insight IN11335, COVID-19’s Effect on Interior Immigration Enforcement and
Detention
; and CRS Legal Sidebar LSB10362, Im m igration Arrests in the Interior of the United States: A Prim er.
85 For background information, see archived CRS Report R44627, Interior Immigration Enforcement: Criminal Alien
Program s
.
86 For more information on permanent and temporary forms of relief from removal, see CRS Report R43892, Alien
Rem ovals and Returns: Overview and Trends
.
87 Applying for asylum while in removal proceedings is referred to as a defensive claim because it acts as a defense to
one’s removal. In contrast, affirmative asylum claims typically occur upon arrival to the United States. For more
information, see CRS Report R45539, Im m igration: U.S. Asylum Policy.
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withholding of removal, Convention Against Torture (CAT) protection, Deferred Enforced
Departure, and deferred action.
Withholding of removal may be given to foreign nationals who can demonstrate a clear
probability (above 50%) that if removed to their home country, they would be persecuted on
account of their race, religion, nationality, membership in a particular social group, or political
opinion. Like asylum, withholding of removal protects people from deportation to a country
where they fear persecution. Unlike asylum, an immigration judge has no discretion and must
grant withholding of removal to alien applicants who meet the requirements.88
CAT is a rarely granted protection from removal for individuals who fear torture in their home
country. To qualify, applicants must demonstrate a clear probability (above 50%) that they wil be
tortured directly by or with the acquiescence of the government of their country of origin.89
Deferred Enforced Departure (DED), which is granted based upon the executive branch’s
independent constitutional authority rather than any specific statutory authority, al ows aliens
relief from removal from the United States for a designated period of time. Aliens receive DED
while in removal proceedings. The Administration may use its discretion when applying DED by
balancing foreign policy, humanitarian, and immigration concerns.90
Deferred action is defined by DHS as “a discretionary determination to defer removal action of an
individual as an act of prosecutorial discretion.” Deferred action is not an immigration status and
lacks a statutory authority; it is a form of administrative discretion. Persons for whom deferred
action is in effect are not considered to be unlawfully present. Examples of deferred action may
include DHS terminating removal proceedings, declining to initiate removal proceedings, or
declining to execute a final order of removal. Approval of deferred action means that no action
wil be taken against a removable alien for a specified time or, in some cases, indefinitely.91
Under the Deferred Action for Childhood Arrivals (DACA) initiative, certain individuals without
a lawful immigration status who were brought to the United States as children and meet other
criteria may be granted deferred action for two years, subject to renewal. DACA recipients can
apply for employment authorization but are not afforded a pathway to a legal immigration status.
DACA was initiated in 2012 by the Obama Administration through an executive branch
memorandum.92 The Trump Administration announced the planned rescission of the DACA
initiative on September 5, 2017, but due to federal court orders enjoining the rescission, DACA
remains in effect.93

88 For more information, see CRS Report R45539, Immigration: U.S. Asylum Policy.
89 For more background, see archived CRS Report RL32276, The U.N. Convention Against Torture: Overview of U.S.
Im plem entation Policy Concerning the Rem oval of Aliens
(available to congressional clients upon request to CRS).
90 For more information, see CRS Report RS20844, Temporary Protected Status and Deferred Enforced Departure.
91 For more information, see U.S. Citizenship and Immigration Services, “Consideration of Deferre d Action for
Childhood Arrivals (DACA), Frequently Asked Questions,” February 4, 2021; and National Immigration Forum,
“Deferred Action Basics,” April 15, 2016.
92 For more information, see CRS Report R45995, Unauthorized Childhood Arrivals, DACA, and Related Legislation .
93 For more information, see CRS Legal Sidebar LSB10497, Supreme Court: DACA Rescission Violated the APA; and
CRS Legal Sidebar LSB10057, District Court Enjoins DACA Phase-Out: Explanation and Takeaways.
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Worksite Enforcement
The INA prohibits the employment of individuals who lack work authorization.94 Its provisions,
sometimes referred to as employer sanctions, make it unlawful for an employer to knowingly
hire, recruit or refer for a fee, or continue to employ an alien who is not authorized to be so
employed. ICE’s worksite enforcement program primarily targets cases involving critical
infrastructure or employers who commit “egregious” violations of criminal statutes and engage in
worker exploitation. Employers who violate prohibitions on unauthorized employment may be
subject to civil monetary penalties and/or criminal penalties.95
Combatting Immigration Fraud
Immigration fraud general y encompasses document fraud and/or benefit fraud. Some view
immigration fraud as a continuum of events, because people may commit document fraud to
engage in benefit fraud.96 The INA addresses immigration fraud in several ways. It makes
misrepresentation (e.g., obtaining a visa by falsely representing a material fact or entering the
United States by falsely claiming U.S. citizenship) a ground for inadmissibility.97 The INA also
has civil enforcement provisions, distinct from removal or inadmissibility proceedings, to
prosecute individuals and entities that engage in immigration document fraud.98 Apart from the
INA, the U.S. Criminal Code classifies knowingly producing or using fraudulent immigration
documents (e.g., visas, border crossing cards) as criminal offenses.99
In addition to relying on document inspection to determine if noncitizens are eligible for federal
benefits, USCIS operates the Systematic Alien Verification for Entitlements (SAVE) system,
which provides federal, state, and local government agencies access to data on immigration
status. USCIS does not determine benefit eligibility; rather, SAVE enables program
administrators to ensure that only those noncitizens and naturalized citizens who meet their own
programs’ eligibility rules actual y receive public benefits.100
Unauthorized Aliens
Determining how to address the unauthorized alien population residing in the United States has
long been among the most divisive immigration issues facing Congress. Unauthorized aliens
consist of those who (1) entered the country without inspection, (2) were admitted on the basis of

94 An estimated 7.6 million unauthorized workers were employed in the U.S. civilian labor force in 2017. Abby
Budiman, “Key Findings about U.S. immigrants,” Pew Research Center, August 20, 2020.
95 T he 1986 Immigration Reform and Control Act (IRCA) requires all employers to verify identity and work
authorization by examining documents presented by new hires and to complete and retain employment eligibility
verification (I-9) forms. For most employers, this system serves as the primary mechanism for verifying employment.
Congress strengthened employment verification with E-Verify, a USCIS-administered program that verifies
employment electronically. While mandatory for federal employment, E -Verify is largely voluntary. For more
information, see CRS Report R40446, Electronic Em ploym ent Eligibility Verification.
96 U.S. House of Representatives, Committee on the Judiciary Subcommittee on Immigration and Claims, Hearing on
Visa Fraud and Im m igration Benefits Application Fraud
, May 20, 1997.
97 INA §212(c), 8 U.S.C. §1182(c).
98 INA §274(c), 8 U.S.C. §1324(c).
99 18 U.S.C. §1546.
100 For more information, see CRS Report RL33809, Noncitizen Eligibility for Federal Public Assistance: Policy
Overview
; and CRS Report R46339, Unauthorized Im m igrants’ Eligibility for COVID-19 Relief Benefits: In Brief.
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fraudulent documents, or (3) violated their authorized period of stay.101 In al three instances, the
aliens violated the INA and may be removed. Aliens who attempt to enter the United States
il egal y and those who assist them also are subject to INA-mandated penalties.
Because the exact number of unauthorized aliens residing in the United States remains unknown,
demographers have developed methods to estimate their population size and characteristics.102
According to recent and widely cited estimates, the size of the unauthorized alien population
increased from about 8.6 mil ion in 2000 to a peak of 12.2 mil ion in 2007, and has fluctuated
between 11.0 and 11.5 mil ion since that time.103 Scholars attribute the general decline and
changing country-of-origin composition in il egal migration flows in recent years to increased
border security, relatively large numbers of alien removals, fluctuating U.S. unemployment, crime
in Central America, and other factors.104
Federal law places various restrictions on unauthorized aliens. In general, they have no legal right
to live or work in the United States and are subject to removal from the country. At the same time,
the INA provides limited forms of immigration relief for some unauthorized aliens to be legal y
admitted to the country, including crime victims and those seeking asylum.
Options proposed for addressing the unauthorized alien population often emphasize reducing its
size. Some approaches would require or encourage unauthorized aliens to depart the United
States. Other strategies would grant qualifying unauthorized residents various immigration
benefits, including an opportunity to obtain legal immigration status.105

101 Estimates suggest that each year, hundreds of thousands of foreign nationals overstay their nonimmigrant visas and
consequently become unauthorized aliens. For more information, see CRS Report R45040, Im migration:
Nonim m igrant (Tem porary) Admissions to the United States
and archived CRS Report RS22446, Nonim m igrant
Overstays: Brief Synthesis of the Issue
. One estimate of the number of nonimmigrant overstays based on 2017 data
suggests that 62% of all unauthorized aliens who arrived in the United States in 2016 became unauthorized after they
overstayed their nonimmigrant visas. See Robert Warren, “ US Undocumented Population Continued to Fall from 2016
to 2017 and Visa Overstays Significantly Exceeded Illegal Crossings for the Seventh Consecutive Year,” Journal on
Migration and Hum an Security
, vol. 7 (2019), pp. 19-22.
102 For background information, see archived CRS Report RL33874, Unauthorized Aliens Residing in the United
States: Estim ates Since 1986
.
103 Julia Heinzel, Rebecca Heller, and Natalie T awil, “Estimating the Legal Status of Foreign-Born People,”
Congressional Budget Office (CBO), Working Paper 2021 -02, March 2021, Figure 9; U.S. Government Accountability
Office (GAO), Departm ent of Hom eland Security: Review of Report on Agency Estim ates of Foreign Nat ionals
Unlawfully Residing in the U.S.
, GAO-19-640R, September 10, 2019; Randy Capps, Julia Gelatt, Ariel G. Ruiz Soto,
and Jennifer Van Hook, Unauthorized Im m igrants in the United States: Stable Num bers, Changing Origins, Migration
Policy Institute, December 2020. DHS’s Office of Immigration Statistics and the Center for Migration Studies have
produced comparable older estimates of the size of the unauthorized population. See Bryan Baker and Nancy Rytina,
Estim ates of the Unauthorized Im m igrant Population Residing in the United States: January 2012 , DHS Office of
Immigration Statistics, March 2013; and Robert Warren, “US Undocumented Population Drops Below 11 Million in
2014, with Continued Declines in the Mexican Undocumented Population,” Journal on Migration and Human Security,
vol. 4 (2016), pp. 1-15.
104 Robert Warren, “Reverse Migration to Mexico Led to US Undocumented Population Decline: 2010 to 2018,”
Journal on Migration and Hum an Security, vol. 8 (2020), pp. 1-10; Randy Capps, Julia Gelatt, Ariel G. Ruiz Soto, and
Jennifer Van Hook, Unauthorized Im m igrants in the United States: Stable Num bers, Changing Origins, Migration
Policy Institute, December 2020; and Jeffrey S. Passel and D’Vera Cohn, U.S. Unauthorized Immigrant Total Dips to
Lowest Level in a Decade
, Pew Research Center, November 27, 2018.
105 For background information, see archived CRS Report R41207, Unauthorized Aliens in the United States: Policy
Discussion
; and archived CRS Report R43097, Com prehensive Im migration Reform in the 113th Congress: Major
Provisions in Senate-Passed S. 744
.
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Author Information

William A. Kandel

Analyst in Immigration Policy



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