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After the massive reorganization of federal agencies precipitated by the creation of the
Department of Homeland Security (DHS), there are now four main federal agencies charged with
securing the United States’ borders: the Bureau of Customs and Border Protection (CBP), which
patrols the border and conducts immigrations, customs, and agricultural inspections at ports of
entry; the Bureau of Immigrations and Customs Enforcement (ICE), which investigates
immigrations and customs violations in the interior of the country; the United States Coast Guard,
which provides maritime and port security; and the Transportation Security Administration
(TSA), which is responsible for securing the nation’s land, rail, and air transportation networks.
This report is meant to serve as a primer on the key federal agencies charged with border security;
as such it will briefly describe each agency’s role in securing our nation’s borders. This report
will be updated as needed.

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n the wake of the tragedy of September 11, 2001, the U.S. Congress decided that enhancing
the security of the United States’ borders was a vitally important component of preventing
I future terrorist attacks. Before September 11, 2001, border security fell piecemeal under the
mandate of many diverse federal departments, including but not limited to: the Department of
Justice (the Immigration and Naturalization Service); the Department of the Treasury (the
Customs Service); the Department of Agriculture (the Animal and Plant Health Inspection
Service); and the Department of Transportation (the Coast Guard).
The Homeland Security Act of 2002 (P.L. 107-296) consolidated most federal agencies operating
along the U.S. borders within the newly formed DHS. Most of these agencies were located in the
Directorate of Border and Transportation Security (BTS), which was charged with securing the
borders; territorial waters; terminals; waterways; and air, land, and sea transportation systems of
the United States; and managing the nation’s ports of entries.1 The lone exception is the U.S.
Coast Guard, which remained a standalone division within DHS. The BTS was composed of three
main agencies: (1) the CBP, which is charged with overseeing commercial operations,
inspections, and land border patrol functions, (2) ICE, which oversees investigations, alien
detentions and removals, air/marine drug interdiction operations, and federal protective services,
and (3) the TSA, which is charged with protecting the nation’s air, land, and rail transportation
systems against all forms of attack to ensure freedom of movement for people and commerce.
On July 13, 2005, the Secretary of DHS, Michael Chertoff, announced the results of the months-
long Second Stage Review (2SR) that he undertook upon being confirmed as DHS Secretary. One
of Secretary Chertoff’s main recommendations, which was agreed to by the DHS Appropriations
Conferees, was the elimination of the BTS Directorate. The Secretary announced the creation of a
new Office of Policy, which, among other things, assumed the policy coordination responsibilities
of the BTS Directorate. The operational agencies that comprised BTS (CBP, ICE, TSA) now
report directly to the Secretary and Deputy Secretary of DHS. The goal of this reorganization was
to streamline the policy creation process and ensure that DHS policies and regulations are
consistent across the department. Additionally, the Federal Air Marshals program was moved out
of ICE and back into TSA to increase operational coordination between all aviation security
entities in the department.
Conceptually speaking, CBP provides the front line responders2 to immigrations and customs
violations and serves as the law enforcement arm of DHS, while ICE serves as the investigative
branch. TSA is charged with securing the nation’s transportation systems, whereas the U.S. Coast
Guard also serves an important border security function by patrolling the nation’s territorial and
adjacent international waters against foreign threats. Combined FY2009 appropriations for the
border security agencies of DHS equaled $30.49 billion,3 and the combined full time equivalent
(FTE) manpower totaled at least 174,251 employees.4

1 Although the functions of CBP and ICE were transferred under the P.L. 107-296, the actual agencies were created by
the George W. Bush Administration. For a more detailed information on DHS, see CRS Report RL31549, Department
of Homeland Security: Consolidation of Border and Transportation Security Agencies, by Jennifer E. Lake.
2 Some argue that the State Department’s Consular posts abroad provide the first line of defense by reviewing visa
applications and determining which foreign nationals will be provided with the documentation required to legally enter
the country.
3 This number, and all the budget numbers in the body of this report, represents the department’s net appropriation.
These appropriation figures include emergency funding from P.L. 111-5, the American Recovery and Reinvestment
Act of 2009. For the cumulative net appropriations to the four agencies under discussion, Division D of P.L. 110-329
provided $28.54 billion in net appropriations, and P.L. 111-5 added $1.95 billion in emergency funding. For a more
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CBP combined portions of the previous border law enforcement agencies under one
administrative umbrella. This involved absorbing employees from the Immigration and
Naturalization Service (INS), the Border Patrol, the Customs Service, and the Department of
Agriculture. CBP’s mission is to prevent terrorists and terrorist weapons from entering the
country, provide security at U.S. borders and ports of entry, apprehend illegal immigrants, stem
the flow of illegal drugs, and protect American agricultural and economic interests from harmful
pests and diseases.5 As it performs its official missions, CBP maintains two overarching and
sometimes conflicting goals: increasing security while facilitating legitimate trade and travel.6 In
FY2009, CBP’s appropriated net budget authority totaled $10.50 billion7 and manpower totaled at
least 54,868 FTE.
Between official ports of entry, the U.S. Border Patrol (USBP)—a component of CBP—enforces
U.S. immigration law and other federal laws along the border. As currently comprised, the USBP
is the uniformed law enforcement arm of the Department of Homeland Security. Its primary
mission is to detect and prevent the entry of terrorists, weapons of mass destruction, and
unauthorized aliens into the country, and to interdict drug smugglers and other criminals. In the
course of discharging its duties the USBP patrols over 8,000 miles of our international borders
with Mexico and Canada and the coastal waters around Florida and Puerto Rico.
At official ports of entry, CBP officers are responsible for conducting immigrations, customs, and
agricultural inspections on entering aliens. As a result of the “one face at the border” initiative,
CBP inspectors are being cross-trained to perform all three types of inspections in order to
streamline the border crossing process. This initiative unifies the prior inspections processes,
providing entering aliens with one primary inspector who is trained to determine whether a more
detailed secondary inspection is required.8
CBP inspectors enforce immigration law by examining and verifying the travel documents of
incoming international travelers to ensure they have a legal right to enter the country. On the
customs side, CBP inspectors ensure that all imports and exports comply with U.S. laws and
regulations, collect and protect U.S. revenues, and guard against the smuggling of contraband.
Additionally, CBP is responsible for conducting agricultural inspections at ports of entry in order

(...continued)
detailed breakdown of DHS appropriations for FY2008, including the gross budget authority provided to each agency,
see CRS Report RL34482, Homeland Security Department: FY2009 Appropriations, coordinated by Jennifer E. Lake
and Blas Nuñez-Neto.
4 All manpower estimates are based upon requested FTEs taken from The Department of Homeland Security,
Congressional Budget Justification, Department of Homeland Security Fiscal Year 2009. Since all DHS agencies under
discussion in this report were fully funded, as well as granted emergency funding, the qualifying phrase of “at least” is
used in conjunction with all FTE estimates.
5 U.S. Congress, House Appropriations Committee, Department of Homeland Security Appropriations Bill, 2005, 108th
Cong., 2nd sess., H.Rept. 108-541.
6 U.S. Customs and Border Protection, Performance and Annual Report: Fiscal Year 2003, p. 25.
7 The gross budget authority appropriated for CBP in FY2009 equaled $11.95 billion. Of this authority, $680 million
was emergency funding from P.L. 111-5.
8 Department of Homeland Security, Office of the Press Secretary, “Homeland Security Announces New Initiatives,”
press release, September 2, 2003.
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to enforce a wide array of animal and plant protection laws. In order to carry out these varied
functions, CBP inspectors have a broad range of powers to inspect all persons, vehicles,
conveyances, merchandise, and baggage entering the United States from a foreign country.9
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ICE merged the investigative functions of the former INS and the Customs Service, the INS
detention and removal functions, most INS intelligence operations, and the Federal Protective
Service (FPS). This makes ICE the principal investigative arm for DHS. ICE’s mission is to
detect and prevent terrorist and criminal acts by targeting the people, money, and materials that
support terrorist and criminal networks.10 As such they are an important component of our
nation’s border security network even though their main focus is on interior enforcement. In
FY2009, ICE appropriations totaled $5.01 billion,11 and the agency had at least 18,965 FTE
employees.
Unlike CBP, whose jurisdiction is confined to law enforcement activities along the border, ICE
special agents investigate immigrations and customs violations in the interior of the United States.
ICE’s mandate includes uncovering national security threats such as weapons of mass destruction
or potential terrorists, identifying criminal aliens for removal, probing immigration-related
document and benefit fraud, investigating work-site immigration violations, exposing alien and
contraband smuggling operations, interdicting narcotics shipments,12 and detaining illegal
immigrants and ensuring their departure (or removal) from the United States.13 ICE is also
responsible for the collection, analysis and dissemination of strategic and tactical intelligence data
pertaining to homeland security, infrastructure protection, and the illegal movement of people,
money, and cargo within the United States.14 Lastly, ICE polices and secures more than 8,800
federal facilities nationwide via the FPS.15

9 For a more detailed analysis of inspections practices along the U.S. border, including the legislative foundation for
CBP powers, a history of inspections practices, and the policy issues involved, refer to CRS Report RL32399, Border
Security: Inspections Practices, Policies, and Issues, by Ruth Ellen Wasem et al.
10 Bureau of Immigrations and Customs Enforcement, Border Security and Immigration Enforcement Fact Sheet, at
http://www.ice.gov/graphics/news/factsheets/061704det_FS.htm.
11 The gross budget authority appropriated for ICE in FY2009 equaled $5.95 billion. Of this authority, $20 million was
emergency funding from P.L. 111-5.
12 Bureau of Immigrations and Customs Enforcement, Office of Investigations Fact Sheet, http://www.ice.gov/graphics/
news/factsheets/investigation_FS.htm.
13 Bureau of Immigrations and Customs Enforcement Organization, at http://www.ice.gov/graphics/about/organization/
index.htm.
14 Bureau of Immigrations and Customs Enforcement, Office of Intelligence Organization, at http://www.ice.gov/
graphics/about/organization/org_intell.htm.
15 Bureau of Immigrations and Customs Enforcement, Organization, at http://www.ice.gov/graphics/about/
organization/index.htm.
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The Coast Guard was incorporated into DHS as a standalone agency by P.L. 107-296. The Coast
Guard’s overall mission is to protect the public, the environment, and U.S. economic interests in
maritime regions—at the nation’s ports and waterways, along the coast, and in international
waters.16 The Coast Guard is thus the nation’s principal maritime law enforcement authority and
the lead federal agency for the maritime component of homeland security, including port security.
Among other things, the Coast Guard is responsible for: evaluating, boarding, and inspecting
commercial ships as they approach U.S. waters; countering terrorist threats in U.S. ports; and for
helping to protect U.S. Navy ships in U.S. ports. A high-ranking Coast Guard officer in each port
area serves as the Captain of the Port and is the lead federal official responsible for the security
and safety of the vessels and waterways in their geographic zone.17 In FY2009, Coast Guard
appropriated budget authority totaled $9.60 billion,18 and the agency had at least 48,930 FTE
military and civilian employees.
As part of Operation Noble Eagle (military operations in homeland defense and civil support to
U.S. federal, state and local agencies), the Coast Guard is at a heightened state of alert protecting
more than 361 ports and 95,000 miles of coastline. The Coast Guard’s homeland security role
includes protecting ports, the flow of commerce, and the marine transportation system from
terrorism; maintaining maritime border security against illegal drugs, illegal aliens, firearms, and
weapons of mass destruction; ensuring that the U.S. can rapidly deploy and resupply military
assets by maintaining the Coast Guard at a high state of readiness as well as by keeping marine
transportation open for the other military services; protecting against illegal fishing and
indiscriminate destruction of living marine resources; preventing and responding to oil and
hazardous material spills; and coordinating efforts and intelligence with federal, state, and local
agencies.19
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The TSA was created as a direct result of the events of September 11 and is charged with
protecting the United States’ air, land, and rail transportation systems to ensure freedom of
movement for people and commerce. The Aviation and Transportation Security Act (ATSA, P.L.
107-71) created the TSA and included provisions that established a federal baggage screener
workforce, required checked baggage to be screened by explosive detection systems, and
significantly expanded FAMS. In 2002, TSA was transferred to the newly formed DHS from the
Department of Transportation; as previously noted, in 2003 the Federal Air Marshal program was
taken out of TSA and transferred to ICE. In FY2006, the program was transferred back to TSA. In

16 U.S. Coast Guard, Overview at http://www.uscg.mil/overview/.
17 For an in depth discussion of the Coast Guard and port security, see CRS Report RS21125, Homeland Security:
Coast Guard Operations - Background and Issues for Congress, by Ronald O’Rourke, and CRS Report RL31733, Port
and Maritime Security: Background and Issues for Congress, by John Frittelli.
18 Of this authority, $240 million was emergency funding from P.L. 111-5.
19 U.S. Coast Guard, Homeland Security Factcard, at http://www.uscg.mil/hq/g-cp/comrel/factfile/Factcards/
Homeland.htm.
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FY2009, TSA appropriations totaled $5.37 billion,20 and the agency had at least 51,488 FTE
employees.
To achieve its mission of securing the nation’s aviation, TSA assumed responsibility for screening
air passengers and baggage—a function that had previously resided with the air carriers. TSA is
also charged with ensuring the security of air cargo and overseeing security measures at airports
to limit access to restricted areas, secure airport perimeters, and conduct background checks for
airport personnel with access to secure areas, among other things.21 However, an opt out
provision in ATSA will permit every airport with federal screeners to request a switch to private
screeners commencing in November 2004.22 Additionally, as a result of the 2SR, the Federal Air
Marshals program has been transferred back to TSA. FAMS is responsible for detecting, deterring
and defeating hostile acts targeting U.S. air carriers, airports, passengers and crews by placing
undercover armed agents in airports and on flights.
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This report has briefly outlined the roles and responsibilities of the four main agencies within the
DHS charged with securing our nation’s borders: the CBP, ICE, the U.S. Coast Guard, and the
TSA. It should be noted, however, that although the Homeland Security Act of 2002 consolidated
all the agencies with primary border security roles in DHS, many other federal agencies are
involved in the difficult task of securing our nation’s borders. Although border security may not
be in their central mission, they nevertheless provide important border security functions. These
agencies include, but are not limited to the Bureau of Citizenship and Immigrations Services
within DHS, which processes permanent residency and citizenship applications, as well as asylum
and refugee processing; the Department of State, which is responsible for visa issuances overseas;
the Department of Agriculture, which establishes the agricultural policies that CBP Inspectors
execute; the Department of Justice, whose law enforcement branches (the Federal Bureau of
Investigation and Drug Enforcement Agency) coordinate with CBP and ICE agents when their
investigations involve border or customs violations; the Department of Health and Human
Services, through the Food and Drug Administration and the Center for Disease Control; the
Department of Transportation, whose Federal Aviation Administration monitors all airplanes
entering American air space from abroad; the Treasury Department, whose Bureau of Alcohol,
Tobacco, and Firearms investigates the smuggling of guns into the country; and lastly the Central
Intelligence Agency, which is an important player in the efforts to keep terrorists and other
foreign agents from entering the country. Additionally, due to their location, state and local
responders from jurisdictions along the Canadian and Mexican borders also play a significant role
in the efforts to secure our nation’s borders.

20 The gross budget authority appropriated for the TSA in FY2009 equaled $7.98 billion. Of this authority, $1,000
million was emergency funding from P.L. 111-5.
21 U.S. General Accounting Office, Aviation Security: Efforts to Measure Effectiveness and Address Challenges, GAO-
04-232T, November 5, 2003, pp. 5-6.
22 See CRS Report RL32383, A Return to Private Security Screening at Airports?: Background and Issues Regarding
the Opt-Out Provision of the Aviation and Transportation Security Act, by Bart Elias.
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Chad C. Haddal

Analyst in Immigration Policy
chaddal@crs.loc.gov, 7-3701

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This report was originally authored by Blas Nuñez-Neto.

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