Mexico Joins Suit Against Arizona's Immigration Law, Citing 'Grave Concerns'

Mexico on Tuesday asked a federal court in Arizona to declare the state's new immigration law unconstitutional, arguing that the country's own interests and its citizens' rights are at stake.

Lawyers for Mexico on Tuesday submitted a legal brief in support of one of five lawsuits challenging the law. The law will take effect July 29 unless implementation is blocked by a court.

The law generally requires police investigating another incident or crime to ask people about their immigration status if there's a "reasonable suspicion" they're in the country illegally. It also makes being in Arizona illegally a misdemeanor, and it prohibits seeking day-labor work along the state's streets.

Until recently, Mexican law made illegal immigration a criminal offense -- anyone arrested for the violation could be fined, imprisoned for up to two years and deported. Mexican lawmakers changed that in 2008 to make illegal immigration a civil violation like it is in the United States, but their law still reads an awful lot like Arizona's.

Arizona's policy, which President Felipe Calderon derided during a recent U.S. trip as "discriminatory," states police can't randomly stop people and demand papers, and the law prohibits racial profiling.

Mexican law, however, requires law enforcement officials "to demand that foreigners prove their legal presence in the country before attending to any issues."