We’re in an unstable equilibrium at the moment, as Anderson explains:

Anyone who thinks that other judges aren’t poised to nationalize this issue is kidding themselves. There are two — and only two — likely outcomes for the debate over the wisdom of redefining marriage in America: Either an amendment will be passed that effectively constitutionalizes DOMA and thereby prevents any states’ redefinition of marriage from becoming binding upon all the other states — while still allowing individual states to redefine marriage as they wish — or else the courts, and (you can bet on it) eventually the Supreme Court, will ultimately declare the redefinition of marriage in some states to be binding upon all the others.

What had been the progressive view — let the states decide — turns out to be less than sustainable for the obvious reason that the federal government needs to make an affirmative decision regarding whether or not to recognize same-sex civil marriages as valid for its own purposes.

In the past, the notion that same-sex civil marriage would soon be nationalized above the objections of people in states that reject the practice was seen as hysterical nonsense, and DOMA was seen by a somewhat larger number of people as a sensible compromise that would enable a state-by-state patchwork of marriage laws for same-sex partners. The consensus has shifted so quickly that I suspect many of the people who once held that view don’t even remember having done so.