"The United States and Mexico have a special relationship as neighbors and partners under the North American Free Trade Agreement (NAFTA). Although relations with Mexico are generally friendly, the enactment of border fence legislation in October 2006 has caused some tension in the bilateral relationship. […] President Calderón was sworn into office on December 1, 2006. During his first weeks in office he has focused on law and order matters, beginning operations against drug cartels and extraditing 15 criminals to the United States on January 19, 2007. U.S. Attorney General Alberto Gonzales praised the extraditions and has praised Calderón's efforts to combat the drug cartels. Drug violence and press freedom remain a concern. Migration and border security concerns have dominated the bilateral relationship in recent years. In September, Congress approved the Secure Fence Act of 2006 (P.L. 109-367) to authorize the construction of a border fence and other barriers along 700 miles of the U.S.-Mexico border. In September 2006, Congress also approved initial funding for fence construction, $1.2 billion, through the FY2007 Department of Homeland Security Appropriations Act. Both the House and Senate approved immigration reform measures (H.R. 4437 and S. 2611, respectively) but did not meet in conference to resolve differences. Principal sticking points include the House provision that criminalizes unlawful presence and Senate provisions to adjust the status of certain illegal immigrants."
CRS Report for Congress, RL32724