Arizona v. United States
In Arizona v. United States, 567 U.S. 387 (2012), the Supreme Court once again emphasized the importance of clear Congressional intent when applying obstacle preemption. See 567 U.S. at 398-99.
The Supreme Court struck down provisions of an Arizona immigration law that would penalize aliens who sought, or engaged in, unauthorized employment, because it "would interfere with the careful balance struck by Congress with respect to unauthorized employment of aliens." 567 U.S. at 406.
With Justice Kagan taking no part in the consideration or decision of the case, writing for a five-to-three majority, which included Chief Justice Roberts and Justices Ginsburg, Breyer, and Sotomayor, Justice Kennedy wrote:
"The correct instruction to draw from the text, structure, and history of the Immigration Reform and Control Act of 1986, 8 U.S.C. 1101 is that Congress decided it would be inappropriate to impose criminal penalties on aliens who seek or engage in unauthorized employment." 567 U.S. at 406.
The Supreme Court ruled that Congressional intent was clear; Congress had considered and rejected penalizing aliens who sought unauthorized employment. See 567 U.S. at 405. The United States Supreme Court noted, "IRCA's express preemption provision, which in most instances bars states from imposing penalties on employers of unauthorized aliens, is silent about whether additional penalties may be imposed against the employees ."
The Arizona Court recognized IRCA's express preemption provision on the employer side but not on the employee side of the equation.