It is well known that the Supreme Court ended its 2012 term with a landmark decision upholding health care legislation. But the United States also made key decisions affecting criminal defense.
In particular, in United States v. Arizona the Court was called upon to decide the constitutionality of Arizona's controversial immigration legislation. The court struck down several provisions of the law on the ground of federal preemption, in other words that the State of Arizona's effort to address illegal immigration would interfere with the authority of the federal government over immigration and customs enforcement. On the other hand, the court upheld a hotly contested piece of the law that mandated an inquiry into immigration status during even many routine detentions. 
This decision was of limited scope, however. The court held that the law was constitutional as written, but that it was premature to determine whether it was necessarily constitutional as applied. The court left it open to another day the question whether immigration checks conducted under the auspices of the law may be unconstitutional as they are enforced in practice. This is not likely the last word on the issue. In the meantime, criminal defense lawyers and civil rights advocates would be well advised to keep careful record of the circumstances in which immigration checks in Arizona are performed.

Alanna D. Coopersmith is a lawyer practicing criminal defense in Oakland, CA. She blogs regularly on criminal defense and constitutional law issues.