Barriers Along the U.S. Borders: Key Authorities and Requirements [April 8, 2015] [open pdf - 527KB]
"Securing the borders is an issue of perennial concern to Congress. Federal law authorizes the Department of Homeland Security (DHS) to construct barriers along the U.S. borders to deter illegal crossings. DHS is also required to construct reinforced fencing along at least 700 miles of the land border with Mexico (a border that stretches 1,933 miles), though Congress has not provided a deadline for its completion. At this time, fence construction has largely been halted, though DHS still needs to deploy fencing along nearly 50 additional miles of the southwest border to satisfy the 700-mile requirement. The primary statute authorizing DHS to deploy barriers along the international borders is Section 102 of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA; P.L. 104-208, div. C). Congress made significant amendments to IIRIRA Section 102 through three enactments--the REAL ID Act of 2005 (P.L. 109-13, div. B), the Secure Fence Act of 2006 (P.L. 109-367), and the Consolidated Appropriations Act, 2008 (P.L. 110-161, div. E). These amendments required that DHS construct hundreds of miles of new fencing along the border, and also provided the Secretary of DHS with broad authority to waive 'all legal requirements' that may impede construction of barriers and roads under IIRIRA Section 102. These statutory modifications, along with increased funding for border projects, resulted in the deployment of several hundred miles of new barriers along the southwest border between 2005 and 2011. In recent years, DHS has largely stopped deploying additional fencing along the border, as the agency has altered its enforcement strategy in a manner that places less priority upon fencing."
CRS Report for Congress, R43975