Cutter, Accommodation, and Separation of Powers
This opinion, particularly it being unanimous, is important for a couple reasons. It clarifies the area between what is protected by the Free Exercise Clause and what is barred by the Establishment Clause, specifically finding that RLUIPA is a valid form of accommodation. And secondly, it vindicates Boerne as a case about formal separation of powers, and not about judicial greediness in the definition of rights.
Amos made the point that "[a]t some point, accommodation may devolve into an unlawful fostering of religion." Accommodation of religion by the government entails giving it money, giving privileges. At some point, Amos assumes, accommodation of religion not mandated by the First Amendment runs up against the Establishment Clause. This was the claim made by Ohio--the burdens placed on the state prison system had the effect of impermissibly advancing religion.
But when pressed at oral arguments by Justice Souter, the Solicitor General for Ohio could not articulate where "accommodation" would be permissible if RLUIPA were held to violate the establishment clause. Justice Souter assumed, and Ohio did not contest, that there must be some room for accommodation, and the question was whether the space between the two clauses was so tight as to bar a statute that just places some burdens for protection of all religious exercise. Justice Ginsburg's opinion describes RLUIPA as fitting in this gap.
It's hard to see why RLUIPA would not fit. It does impose burdens on the states, but these burdens do not distinguish based on particular religions, as is evident from the beliefs of the plaintiffs (the Satanist, Wicca, and Asatru religions, and the Church of Jesus Christ Christian). If RLUIPA establishes religion, then we're on a slippery slope to doing away with tax exemptions and any legislation that protects all religious exercise. This would close the gap, making the Free Exercise the only possible form of protection, since Congress' role would be gone.
The second reason I think the opinion is important is that there is no discussion of the separation of powers issues that there were in RFRA. The Court has been criticized by civil rights and religious rights advocates as being greedy with its protecting of rights, and using separation of powers in the Boerne line of cases pretextually.
But Justice Ginsburg's opinion does not even take up the issue, and it was barely discussed at arguments. As I previously noted, and as argued in an amicus brief by Marty Lederman on behalf of Senators Hatch and Kennedy, the Commerce Clause and Spending Clause attacks on the statute were weak, and there was no reason to view this case in light of Boerne. Boerne was true formalism, was not a pretext for a judicial power grab in the definition of rights. Boerne held, and Cutter confirms, that Congress can participate in the protection of freedoms; it need only play by the rules.
ALSO: Marty Ledermann at SCOTUSBlog has this discussion.