Arizona v. United States: A Limited Role for States in Immigration Enforcement [September 10, 2012] [open pdf - 316KB]
"On June 25, 2012, the Supreme Court issued its much-anticipated decision in 'Arizona v. United States,' ruling that some aspects of an Arizona statute intended to deter unlawfully present aliens from remaining in the state were preempted by federal law, but also holding that Arizona police were not facially preempted from running immigration status checks on persons stopped for state or local offenses. In reaching these conclusions, the Supreme Court made clear that opportunities for states to take independent action in the field of immigration enforcement are more constrained than some had previously believed. In recent years, several states and localities have adopted measures intended to deter the presence of unauthorized aliens within their jurisdiction. An Arizona measure enacted in 2010, commonly referred to as S.B. 1070, arguably represents the vanguard of these attempts to test the legal limits of greater state involvement in immigration enforcement. The major provisions of S.B. 1070 can be divided into two categories: (1) those provisions seeking to bolster direct enforcement of federal immigration law by Arizona law enforcement, including through the identification and apprehension of unlawfully present aliens; and (2) those provisions that criminalize conduct which may facilitate the presence of unauthorized aliens within the state."
CRS Report for Congress, R42719