Order Code RS22026
Updated September 15, 2006
CRS Report for Congress
Received through the CRS Web
Border Security: Fences Along the
U.S. International Border
Blas Nuñez-Neto
Analyst in Domestic Security
Domestic Social Policy Division
Stephen R. Viña
Legislative Attorney
American Law Division
Summary
The 109th Congress passed provisions to facilitate the completion of a three-tiered,
14-mile fence, along the border near San Diego in the REAL ID Act of 2005 (H.R. 418),
which was subsequently added to H.R. 1268, the Emergency Supplemental
Appropriations Act, and signed into law on May 11, 2005 (P.L. 109-13). The new
provisions allow the Secretary of the Department of Homeland Security to waive all
legal requirements
determined necessary to ensure expeditious construction of
authorized barriers and roads. In September of 2005, the Secretary announced that he
was using this authority to waive a number of mostly environmental and conservation
laws. Other bills in the 109th Congress, including House-passed H.R. 4437 and H.R.
6061 and Senate-passed S. 2611, would call on the Secretary to construct reinforced
fencing and vehicle barriers along vast portions of the southwest border. This report
outlines the issues involved with DHS’s completion of the San Diego border fence and
highlights some of the major legislative and administrative developments regarding the
construction of new border fences. This report will be updated as warranted.
Background
The United States Border Patrol (USBP) is the lead federal agency charged with
securing the U.S. international land border with Mexico and Canada. In the early 1990s,
the USBP incorporated the construction of physical barriers directly on the border into
their National Strategic Plan as part of the “Prevention Through Deterrence” strategy,
which called for reducing unauthorized migration by placing agents and resources directly
on the border abutting population centers. The USBP first constructed border fencing in
the San Diego sector, which extends inland from the Pacific Ocean along the international
land border with Mexico, and covers approximately 7,000 square miles of territory.
Located north of Tijuana and Tecate, Mexican cities with a combined population of 2
Congressional Research Service ˜ The Library of Congress

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million people, the sector features no natural barriers to entry by unauthorized migrants
and smugglers.1 Using the broad powers granted to the Attorney General (AG) to control
and guard the U.S. border,2 in 1990 the USBP began erecting a physical barrier to deter
illegal entries and drug smuggling in the San Diego sector. The ensuing “primary” fence
was completed in 1993 and covered the first 14 miles of the border, starting from the
Pacific Ocean, and was constructed of 10-foot-high welded steel.3 This fence (and the
subsequent three-tiered fence, see discussion below) was constructed with the assistance
of the Department of Defense’s (DOD’s) Army Corps of Engineers.
According to the Bureau of Customs and Border Protection, the primary fence, in
combination with various labor intensive USBP enforcement initiatives along San Diego
border region (i.e., Operation Gatekeeper), proved to be quite successful but fiscally and
environmentally costly.4 For example, as undocumented aliens and smugglers breached
the primary fence and attempted to evade detection, USBP agents were often forced to
pursue the suspects through environmentally sensitive areas. It soon became apparent to
immigration officials and lawmakers that the USBP needed, among other things, a “rigid”
enforcement system that could integrate infrastructure (i.e., a multi-tiered fence and
roads), manpower, and new technologies to further control the border region.
The concept of a three-tiered fence system was first recommended by a 1993 Sandia
Laboratories study commissioned by the Immigration and Naturalization Service (INS).
The study concluded that aliens attempting to enter the United States from Mexico had
shown remarkable resourcefulness in bypassing or destroying obstacles in their path,
including the existing primary fence, and postulated that “[a] three-fence barrier system
with vehicle patrol roads between the fences and lights will provide the necessary
discouragement.”5 Congress responded to these enforcement needs, in part, with the
passage of the Illegal Immigration Reform and Immigration Responsibility Act (IIRIRA)
of 1996.6 This comprehensive law, among other things, expanded the existing fence by
authorizing the INS to construct a triple-layered fence along the same 14 miles of the US-
Mexico border near San Diego. Since 1990, Congress has also included language in DOD
appropriations bills allowing the DOD to assist federal agencies in counter-drug activities,
1 U.S. Department of Justice, Office of the Inspector General, Operation Gatekeeper: An
Investigation Into Allegations of Fraud and Misconduct
, July 1998.
2 See e.g., 8 U.S.C. §1103 (a)(5).
3 U.S. Government Accountability Office, Border Control — Revised Strategy is Showing Some
Positive Results
, GAO/GGD-95-30, Jan. 31, 1995.
4 See California Coastal Commission, W 13a Staff Report and Recommendation on Consistency
Determination
, CD-063-03, Oct. 2003, at 14-16 (stating that construction of the primary fence
significantly assisted the USBP’s efforts in deterring smuggling attempts via drive-throughs using
automobiles and motorcycles). (Hereafter CCC Staff Report.)
5 Peter Andreas, “The Escalation of U.S. Immigration Control in the Post-NAFTA Era,” Political
Science Quarterly
, vol. 113, no. 4, winter 1998-1999, p. 595.
6 See P.L. 104-208, Div. C. IIRIRA was passed as part of the Omnibus Consolidated
Appropriations Act of 1997.

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including the construction of fencing and roads to reduce the flow of narcotics into the
country.7 In 2001, this power was re-authorized through FY2006.8
Section 102 of IIRIRA — Improvement of Barriers at the Border
Section 102 of IIRIRA concerns the improvement and construction of barriers at our
international borders. Section 102(a) appears to give the AG9 broad authority to install
additional physical barriers and roads “in the vicinity of the United States border to deter
illegal crossings in areas of high illegal entry into the United States.” The phrase vicinity
of the United States border
is not defined in the Immigration and Nationality Act (8
U.S.C. §1101 et seq.) or in immigration regulations. The section also does not stipulate
what specific characteristics would designate an area as one of high illegal entry.
Section 102(b) mandates that the AG construct a barrier in the border area near San
Diego. Specifically, §102(b) directs the AG to construct a three-tiered barrier along the
14 miles of the international land border of the United States, starting at the Pacific Ocean
and extending eastward. Section 102(b) ensures that the AG will build a barrier, pursuant
to his broader authority in §102(a), near the San Diego area, although there is some debate
whether IIRIRA requires continuous triple fencing and roads for the entire 14-mile
corridor.10 Section 102(b) also provides authority for the acquisition of necessary
easements, requires that certain safety features be incorporated into the design of the
fence, and authorizes an appropriation not to exceed $12 million.
Section 102(c) — before its amendment in the REAL ID Act as part of P.L. 109-13
— waived the Endangered Species Act (ESA) of 1973 (16 U.S.C. §§1531 et seq.) and
the National Environmental Policy Act (NEPA) of 1969 (42 U.S.C. §§4321 et seq.), to
the extent the AG determined necessary, in order to ensure expeditious construction of
the barriers authorized to be constructed under §102.11 The waiver authority in this
provision appears to apply both to barriers that may be constructed in the vicinity of the
border
under §102(a) and to the barrier that is to be constructed near the San Diego area
under §102(b). The REAL ID Act amended §102(c) to, among other things, authorize the
waiver of all legal requirements determined necessary for the construction of the barriers
and roads authorized to be constructed in §102 of IIRIRA.
7 See P.L. 101-510, Div. A, Title X, §1004; P.L. 102-190, Div A, Title X, Part G, §1088; P.L.
102-484, Div A, Title X, Subtitle E, §1041(a)-(d)(1); P.L. 103-160, Div A, Title XI, Subtitle C,
§1121(a), (b); P.L. 103-337, Div A, Title X, Subtitle B, §1011(a).
8 P.L. 107-107, Title X, Subtit. C, §1021 (amending §1004 of the National Defense Authorization
Act of Fiscal Year 1991, P.L. 101-510, codified at 10 U.S.C. §374 nt.).
9 Although the law still cites to the Attorney General, the authorities granted by this section now
appear to rest with the Secretary of DHS. See The Homeland Security Act of 2002, P.L. 104-208,
§§102(a), 441, 1512(d) and 1517 (references to the Attorney General or Commissioner in statute
and regulations are deemed to refer to the Secretary).
10 See CCC, Staff Report, at 7 nt. 2 and p. 23 nt. 4.
11 CBP apparently never used this waiver authority and even published a Final Environmental
Impact Study pursuant to NEPA and received a non-jeopardy Biological Opinion from the U.S.
Fish and Wildlife Service under the ESA. CCC, Staff Report, at 14.

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San Diego Sector Apprehensions
Apprehension statistics have long been used as a performance measure by the USBP.
However, the number of apprehensions may be a misleading statistic for several reasons,
including the data’s focus on events rather than people12 and the absence of reliable
estimates for how many aliens successfully evade capture. These factors aside, however,
apprehensions data remain the best way to gain a glimpse into the reality facing USBP
agents and the trends in unauthorized migration along the border. As Figure 1 shows,
apprehensions remained stable during the early 1990s in the San Diego sector despite the
construction of the “primary” fence in 1993.
Figure 1. USBP Apprehensions, San Diego Sector, FY1992-FY2004
6 0 0 0 0 0
5 0 0 0 0 0
4 0 0 0 0 0
3 0 0 0 0 0
2 0 0 0 0 0
1 0 0 0 0 0
0
1 9 9 2
1 9 9 3
1 9 9 4
1 9 9 5
1 9 9 6
1 9 9 7
1 9 9 8
1 9 9 9
2 0 0 0
2 0 0 1
2 0 0 2
2 0 0 3
2 0 0 4
S o u r c e : C R S P r e s e n t a t i o n o f C B P D a t a
After the IIRIRA’s mandate for increased enforcement along the Southwest border
in 1996, including construction of the triple-fence, apprehensions dropped rapidly in the
San Diego sector in the late 1990s — from 480,000 in FY1996 to 100,000 in FY2002.
Although some of this reduction may have been due to the construction of the triple-fence,
the number of agents assigned to the San Diego sector also increased significantly over
this period — from 980 agents in 1993 to 2,274 in 1998.13 Additionally, the number of
underground sensors deployed in the San Diego sector almost tripled from 1993 to 1998,
and the fleet of vehicles increased by over 150% over the same period.14
The increase in manpower and resources reflected the USBP’s policy of re-routing
unauthorized migration away from population centers to remote border regions where
their agents have a tactical advantage over border-crossers. Other sectors, especially the
remote Tucson sector in Arizona, saw apprehensions increase significantly in the late
1990s. Proponents of border fences point to the drastic reduction in apprehensions along
the San Diego sector as tangible proof that these fences succeed in their goal of reducing
cross-border smuggling and migration where they are constructed. Opponents attribute
part of the decrease in apprehensions to the increase in manpower and resources in the
sector and (pointing to the increase in apprehensions in less-populated sectors) contend
that the fence only succeeds in re-routing unauthorized migration. Additionally, some
12 If the same person is apprehended multiple times attempting to enter the country in one year,
each apprehension will be counted separately by the USBP in generating their apprehension
statistics. This means that apprehension statistics may overstate the number of aliens apprehended
each year.
13 CBP data provided to CRS on Jan. 12, 2004.
14 U.S. Citizenship and Immigration Services, “Operation Gatekeeper Fact Sheet,” (July 14,
1998) available at [http://uscis.gov/graphics/publicaffairs/factsheets/opgatefs.htm].

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believe the reduction in apprehensions can be attributed to the economic recession in the
United States which depressed the job market, while others note that the reduction began
in the late 1990s when the economy was still undergoing a period of robust growth.
Recent Developments
The Controversy. Of the 14 miles authorized to be constructed, nine miles of the
triple-fence have been completed. Two sections, including the final three-mile stretch of
fence that leads to the Pacific Ocean, have not been finished. In order to finish the fence,
the USBP proposed to fill a deep canyon known as “Smuggler’s Gulch” with over 2
million cubic yards of dirt. The triple-fence would then be extended across the filled
gulch. California’s Coastal Commission (CCC), however, objected to and essentially
halted the completion of the fence in February 2004, because it determined that the CBP
had not demonstrated, among other things, that the project was consistent “to the
maximum extent practicable” with the policies of the California Coastal Management
Program — a state program approved under the federal Coastal Zone Management Act
(CZMA) (16 U.S.C. §§1451-1464).15
The CZMA requires federal agency activity within or outside the coastal zone that
affects any land or water use or natural resource of the coastal zone to be carried out in
a manner that is consistent to the maximum extent practicable with the policies of an
approved state management program.16 Specifically, the CCC was concerned with the
potential for significant adverse effects on (1) the Tijuana River National Estuarine
Research and Reserve; (2) state and federally listed threatened and endangered species;
(3) lands set aside for protection within California’s Multiple Species Conservation
Program; and (4) other aspects of the environment. The CCC held that Congress did not
specify a particular design in the IIRIRA and that the CBP failed to present a convincing
argument that the less environmentally damaging alternative projects it rejected would
have prevented compliance with the IIRIRA.
Congressional Action. Although the IIRIRA allowed DHS to waive two major
environmental laws, it did not include the CZMA in its purview. Congress, accordingly,
attempted to pass legislation to facilitate the completion of the fence. The final version
of the House-passed version of the intelligence bill in the 108th Congress, S. 2845, for
example, contained language that would have added the CZMA, among a wide array of
other environmental, conservation, and cultural restrictions, to the list of laws and
regulations that DHS could waive in its construction of border barriers.17 This section
was ultimately removed during the conference process, and no border fence type provision
was included in the intelligence bill that was signed into law (P.L. 108-458).
In the 109th Congress, H.R. 418, the REAL ID Act of 2005, contained language
requiring the Secretary of DHS to waive all laws necessary to ensure expeditious
construction of the security barriers. H.R. 418 was passed by the House as a stand-alone
piece of legislation, but was also attached as an amendment to House-passed H.R. 1268,
15 See CCC, Staff Report, at 5-7.
16 16 U.S.C. §1456(c).
17 S. 2845 EAH, §3131.

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the emergency supplemental appropriations bill for FY2005. During conference,
language was revised in H.R. 1268 to “authorize,” instead of “require,” the Secretary of
DHS to waive all “legal requirements,” instead of “all laws.” The conferees also added
a new provision that would make such waiver decisions effective upon publication in the
Federal Register. Language was also added granting federal district courts exclusive
jurisdiction to review claims alleging that the actions or decisions of the Secretary violate
the U.S. Constitution, and allowing district court rulings to be reviewed only by the U.S.
Supreme Court. H.R. 1268 was signed into law on May 11, 2005 (P.L. 109-13).
The waiver authority provided in §102 appears to be a broad grant of authority
because, in part, it authorizes the waiver of all legal requirements determined necessary
by the Secretary for the expeditious construction of authorized barriers and only allows
judicial review for constitutional claims. Furthermore, these claims can only be appealed
to the Supreme Court (i.e, there is no intermediate appellate review), whose review is
discretionary. Moreover, because §102 of the REAL ID Act amends only the waiver
provision of §102 of IIRIRA, the new waiver authority appears to apply to all the barriers
that may be constructed under IIRIRA — that is, both to barriers constructed in the
vicinity of the border and to the barrier that is to be constructed near the San Diego area.
Other bills in the 109th Congress also contain border fence provisions. For example,
the House passed H.R. 4437, the Border Protection, Antiterrorism, and Illegal
Immigration Control Act of 2005, which would amend §102(b) of IIRIRA to require the
construction of at least two layers of reinforced fencing and the implementation of
surveillance measures (lighting, sensors, cameras) along roughly 730 miles of the
southwest border. The House also passed the Secure Fence Act of 2006 (H.R. 6061),
which would authorize more than 700 miles of two-layered reinforced fencing along
selected populated areas of the southwest border. Relatedly, the Comprehensive
Immigration Reform Act of 2006 (S. 2611), as passed by the Senate, would replace and
expand the current fencing in the Border Patrol’s Tucson and Yuma Sectors with a
reinforced double- or triple-layered fence and would require at least 370 miles of new
triple-fencing and 500 miles of vehicle barriers along the southwest border.
Construction. The military has now begun rebuilding the San Diego border fence.
On September 22, 2005, DHS published a Federal Register notice declaring the waiver
of, in their entirety: (1) the NEPA; (2) the ESA; (3) the CZMA; (4) the Federal Water
Pollution Control Act (33 U.S.C. §§1251 et seq.); (5) the National Historic Preservation
Act (16 U.S.C. §§470 et seq.); (6) the Migratory Bird Treaty Act (16 U.S.C. §§703 et
seq
.); (7) the Clean Air Act (42 U.S.C. §§7401 et seq.); and (8) the Administrative
Procedure Act (5 U.S.C. §§551 et seq.).18 Relatedly, plans to construct a 123 mile vehicle
barrier, consisting of steel beams planted five feet deep into concrete bases, along the
Arizona border are also moving forward.19 The FY2006 DHS Appropriations Act
provides, within the CBP construction account, $35 million for the construction of the
border fence in San Diego and $35 million for tactical infrastructure in the USBP’s
Tucson sector (P.L. 109-90).
18 The waiver also includes all federal, state, or other laws and regulations deriving from the
listed laws.
19 Jonathan Athens, Officials say OK to Border Fence, YumaSun.com (July 20, 2005) available
at [http://sun.yumasun.com/google/ysarchive14980.html].