Today's announcement that the Obama administration will file an amicus brief with the Supreme Court asking that it overturn California's ban on gay marriage suggests that the president's support for gay rights — once considered lacking, but ever evolving — has now checked nearly every box.

When the president included the Stonewall riots among the nation's key civil rights moments in his second inaugural address, activists rejoiced — warily. The Associated Press quoted Jon Davidson of Lambda Legal: "I was very moved, but there's a lot more to do in the four years to come. ... It's not like everything is fine." On the top of the list for many was the president taking a position on two key same-sex marriage cases currently on the Court's docket.

Which he has now done. Last weekend, the administration filed a brief in United States v. Windsor (which you can read here), arguing that the Defense of Marriage Act violates the equal protection clause of the Fifth Amendment by establishing two unequal classes for marriage, gay and straight. Obama had already decided in 2011 to stop defending DOMA in court; the brief moved the administration from "neutral" to "opposed." And then today came the decision to formally oppose California's Proposition 8, which in 2008 extended the state's definition of marriage to exclude same-sex couples. A blanket rejection of gay marriage bans under the equal protection clause in either case would have sweeping ramifications, basically making gay marriage legal in every state at once.

At one point, it didn't look like Obama would be the president on duty when such a thing happened. NBC News notes how today's announcement differs from the administration's past position:

After first suggesting it would not get involved, the Obama administration will file a friend-of-the-court brief late today in support of the two gay couples who launched the fight over the issue four years ago, the officials said. Today is the last day for filing briefs in support of the couples' position.

The administration last year signaled it might stay on the sidelines. In May, when President Obama first said that "same-sex couples should be able to get married," he added that it was not a matter for the federal government.

That was during Obama's sit-down with Robin Roberts, during which the president indicated that he was "going through an evolution on this issue." By nearly any account — even that of staunch critics of the president — that evolution is all but complete.