There is a good deal of celebration out there about today’s Supreme Court arguments over the Defense of Marriage Act, because they seemed to demonstrate that a majority of the justices see DOMA as unconstitutional, meaning the law may be in deep trouble. And that’s certainly good news.

However, having read through the transcript, it’s hard to miss the downside to today’s events. Specifically, Justice Anthony Kennedy was maddeningly opaque — and even uninterested — when it came to the “heightened scrutiny” question. This suggests the possibility that even if DOMA is struck down, the Court may not clarify its position on that question, which in turn will not give gay advocates the additional weapon they had hoped for against state laws banning gay marriage.

Again and again, Obama Solicitor General Donald Verrilli repeated the administration’s argument against DOMA: Laws that classify people based on sexual orientation must be subjected to heightened scrutiny — i.e. they need to have an extremely compelling policy rationale — and when they are, it is revealed that they violated the equal protection clause of the Constitution. But Kennedy didn’t seem to engage this argument. Instead, as SCOTUSblog’s Lyle Denniston puts it, he was much more focused on the idea that DOMA “intruded too deeply into the power of the states to regulate marriage.”

That could very well mean DOMA will be struck down — which is great — but it doesn’t settle how SCOTUS views the question of whether sexual orientation classifications merit heightened scrutiny and hence violate the equal protection clause. As Denniston notes:

It was not apparent that Verrilli was making much headway with his argument that any law that treats gays and lesbians less favorably, because of their sexual identity, should have to satisfy a stricter constitutional test.
The Court, although it has been dealing with gay rights cases for years, has never spelled out a specific constitutional standard for judging laws that allegedly discriminate based on homosexuality.   The indications on Wednesday were that the DOMA case might be decided without supplying such a standard, since a decision based on interference with states’ prerogatives would not require the creation of a test based on equality principles.

And that would be unfortunate. If the Court rules on narrow procedural grounds on Prop 8 (which Verrilli also challenged on “heightened scrutiny” grounds), and if it strikes down DOMA in the fashion Denniston suggests, the Court may end up hearing these two cases without spelling out its constitutional standards for evaluating laws that discriminate based on sexual orientation. Advocates are hoping the Court would do this, because if it does, it seems highly unlikely that other state laws banning gay marriage would clear those standards, making it more likely that they would ultimately get struck down as unconstitutional. If the court doesn’t do this, advocates won’t gain the additional weapon they’d hoped would help them topple those laws. (fixed)

To be sure, if marriage is returned to California via a narrow procedural ruling, it would dramatically increase the number of Americans who have access to legal gay marriage. Combine that with DOMA getting struck down, and that would add up to a major, landscape shifting victory in its own right. Public opinion is on the march, and the only real remaining question is whether gay rights advocates will be forced to win this battle one state at a time. All in all, it’s been a good week for equality.