July 6, 2010 -- The U.S. Attorney General filed suit against the State of Arizona, seeking to prevent its new immigration law, S.B. 1070, from going into effect.    S.B. 1070 includes a provision that requires, in the context of a lawful police stop, the verification of an individual's immigration status when there is a reasonable suspicion that the individual is unlawfully present in the U.S.    This mandatory provision includes a private right of action, allowing any legal resident of Arizona to sue for monetary damages if he can show that any official or agency has adopted a policy that limits the enforcement of immigration laws to less than the full extent allowed under federal law.  The state law also creates several immigration-related crimes under state law. 

The lawsuit contends that the Arizona law violates the Supremacy Clause of the U.S. Constitution, and unconstitutionally interferes with the federal government's immigration laws.   The U.S. Constitution grants the U.S. Congress the authority to regulate immigration.  The Complaint of the lawsuit argues that individual states may not establish their own immigration policy or enact immigration laws that interfere with federal law.  Allowing individual states to enact their own immigration laws would result in a "patchwork" of state and local immigration laws throughout the country.