Nicholas Stephanopoulos makes a really important point:
Although it’s superficially appealing, the argument for judicial deference is wrong. The ability of gay rights groups to win ordinary political battles is actually quite limited. Much more common than the imposition of pro-gay policies on a disapproving majority is the reverse scenario: the failure to enact such policies even when they’re supported by a popular majority. Judicial intervention may therefore be necessary because, regrettably, this is not an area in which the political process can be trusted.
I agree with assumptions that the turn of public opinion in favor of same-sex marriage is likely to be permanent. But the problem is that people greatly overestimate the effect of public opinion on public policy. This is one of the really key problems with the “Roe was counterproductive” argument. The assumption is that because outright bans on abortion are unpopular in most states, they were doomed whether the Supreme Court intervened or not. The problem is this isn’t how actually how American politics actually works. Madisonian institutions protect the status quo, and people vote for bundles of policy positions, not a la carte. Parties can maintain majority status while maintaining unpopular positions on individual issues, and this goes triple when (as is the case with abortion regulations and prohibitions) the policy disproportionately burdens people with the least political influence. Which is why the movement to legalize abortion had essentially stalled by 1973, with abortion having been decriminalized in only 4 states and the District of Columbia. More battles for legalization would eventually would have been won, but abortion would have remained illegal in many states, perhaps a majority.
And the same thing is true with same-sex marriage. Public opinion may well favor same-sex marriage in the vast majority of states where it’s now illegal by the end of the decade. But this doesn’t mean that people not directly affected by the issue will instantly become single-issue voters unwilling to settle for anything less than full equality. Plenty of affluent suburbanites in states where SSM is still illegal will be happy to keep voting for Republicans who oppose SSM even if they nominally favor it. To argue that the Supreme Court should stay its hand because most states will soon grant marriage equality is to rest on assumption with very little basis.
There’s a final, immoral variation of the argument, which is that the Supreme Court staying its hand is a good thing because it will hand Democrats an issue to beat Republicans over the head with. Even leaving aside the fact that the political benefits of being on the right public opinion side of SSM are almost certainly overstated (just as the political benefits Republicans got from opposed SSM in the previous two decades were greatly overstated), as I’ve said this argument only works if you trivialize the issue. People’s dignity and human rights aren’t a pawn to be used to produce (very modest) political benefits; when they can be advanced they should be.