"The United States and Mexico have a close and complex bilateral relationship, with extensive economic linkages as neighbors and partners under the North American Free Trade Agreement (NAFTA). In recent years, security issues have dominated U.S.-Mexican relations, as the United States has supported Mexican President Felipe Calderón's campaign against drug trafficking organizations (DTOs) through bilateral security cooperation initiatives including the Mérida Initiative, an anti-crime and counterdrug assistance package first funded in FY2008. Immigration and border security have also returned to the forefront of the bilateral agenda since Arizona enacted a controversial state law against illegal immigration (S.B. 1070) on April 23, 2010. In late July 2010, a federal judge blocked large parts of S.B. 1070 from taking effect pending the results of a U.S. Department of Justice lawsuit challenging its constitutionality. In response to rising concerns about border security, President Obama has deployed 1,200 National Guard troops to support law enforcement efforts along the U.S.-Mexico border and Congress has approved $600 million in supplemental funds for border security (P.L. 111-230). Now in the fourth year of his six-year term, President Calderón of the conservative National Action Party (PAN) is focused on restarting the Mexican economy, which contracted by 7% in 2009 (largely as a result of the U.S. recession), and combating drug traffickers and organized criminal groups. Although the Calderón Administration has arrested several top drug kingpins, the persistent and increasingly brazen violence committed by the DTOs has led to significant criticism of Calderón's anti-drug strategy."
CRS Report for Congress, RL32724