Can treaty power allow the federal government to act outside its enumerated powers? Read Professor Volokh's discussion of the Court's recent decision of United States v. Lara.

For instance, the Supreme Court has struck down the Religious Freedom Restoration Act, as applied to the states, on the grounds that it exceeds the federal government's enumerated powers -- if the President signs a treaty mandating all signatories to exempt religious objectors from many generally applicable laws, the Senate ratifies the treaty, and Congress reenacts RFRA to implement the treaty, would that be constitutional? (Some people argue that our human rights treaty obligations already provide an authority for such a statute, but I'm skeptical.)

The question isn't whether the Treaty Power can trump the Bill of Rights and other individual rights protections can't be trumped by treaty; it's pretty well-established that it can't. Rather, the question is whether it provides an independent source for federal power, or whether it's governed by the article I limitations on federal power as well as by the individual rights limitations.

Volokh observes that Rehnquist and O'Connor, despite their standard conservative view in respect to limiting federal power, endorsed the 1920 Missouri v. Holland precedent that allows treaties to authorize federal power where such pwer would othewise be absent. Still, the issue was not taken up head-on; I'd be interested to see the direct opinions on topic.