Supreme Court strikes down three of Arizona SB 1070's four provisions as federally preempted

The Supreme Court ruled 5-3 in Arizona v. United States that three of Arizona SB1070 four challenged provisions were preempted by federal immigration law. Justice Anthony Kennedy wrote the majority opinion, joined by Chief Justice Roberts and Justices Ginsburg, Breyer, and Sotomayor, holding that states cannot create independent immigration crimes, cannot make warrantless arrests based solely on civil deportability, and cannot require immigrants to carry federal registration documents. The Court preserved SB1070 Section 2(B) -- the show me your papers provision -- allowing officers to check immigration status during stops, but stressed that even this provision must be implemented without conflicting with federal enforcement priorities. The ruling cemented the principle that immigration enforcement requires one voice from the federal government and became the primary precedent that Judge David Ezra later cited when blocking Texas SB4.