From the Summary: "This report outlines the issues involved with DHS's construction of the San Diego border fence and highlights some of the major legislative and administrative developments regarding its completion; it will be updated as warranted. Congress first authorized the construction of a 14-mile, triple-layered fence along the U.S.-Mexico border near San Diego in the Illegal Immigration Reform and Immigration Responsibility Act (IIRIRA) of 1996. By 2004, only nine miles had been completed, and construction was halted because of environmental concerns. The 109th Congress subsequently passed the REAL ID Act (P.L. 109-13, Div. B), which contained provisions to facilitate the completion of the 14-mile fence. These provisions allow the Secretary of Homeland Security to waive all legal requirements determined necessary to ensure expeditious construction of authorized barriers and roads. In September 2005, the Secretary used this authority to waive a number of mostly environmental and conservation laws. Subsequently, the Secure Fence Act of 2006 (P.L. 109-367) removed the specific IIRIRA provisions authorizing the San Diego fence and added provisions authorizing five stretches of two-layered reinforced fencing along the southwest border. While the specific authorization of the San Diego fence was deleted, the project appears permissible under a separate, more general authorization provision of IIRIRA. In the 110th Congress, S.Amdt. 1150, the Secure Borders, Economic Opportunity, and Immigration Reform Act of 2007, which has been proposed in the nature of a substitute to S. 1348, the Comprehensive Immigration Reform Act of 2007, would amend § 102 of IIRIRA to once again expressly authorize the construction of the San Diego fence."
CRS Report for Congress, RS22026