The NAACP’s decision to support marriage equality explicitly is early evidence that President Obama’s announcement about same sex marriage was a tipping point in American politics and opinion.

As we discussed, President Obama’s disclosure, in a soft interview, about how his position on gay marriage had “evolved,” was limited. He didn’t make a major policy address, nor did he propose any legislation to advance the cause. Nonetheless, his new public position was a signal and encouragement for others to go further.

The NAACP surfed the attention President Obama had generated to announce a position that had been in development for several years. At a meeting of its Board of Directors, the longstanding civil rights organization announced:

The NAACP Constitution affirmatively states our objective to ensure the “political, educational, social and economic equality” of all people. Therefore, the NAACP has opposed and will continue to oppose any national, state, local policy or legislative initiative that seeks to codify discrimination or hatred into the law or to remove the Constitutional rights of LGBT citizens. We support marriage equality consistent with equal protection under the law provided under the Fourteenth Amendment of the United States Constitution. Further, we strongly affirm the religious freedoms of all people as protected by the First Amendment.

Of course, the NAACP viewed the issue through the lens of its history and constitutional orientation, even as it addressed issues founder W.E.B. Du Bois couldn’t imagine surfacing in American politics. Organizations that survive evolve to address new issues. And note the way the NAACP’s board invoked the equal protection clause in the 14th amendment, ratified after the Civil War with the rights of former slaves in mind. Constitutional interpretation evolves too.

Like President Obama’s statement, the NAACP’s position is a signal to other organizations and publics about the importance of addressing marriage equality. If Obama and the NAACP are reading the political tea leaves correctly, political organizations that don’t endorse marriage equality (at least on one half of the political spectrum) will soon seem out of touch. The Democratic Party will surely have a marriage equality plank in its platform this year. As each new group flips on this issue, the pressure and incentives for others to do so increases.

This is what “tipping point” means, as Philip Cohen has been ranting about over at Family Inequality.

We’re always so immersed in the battle of the moment that it’s hard to see how much our world has changed, more slowly than activists wanted–but far more dramatically than most imagined possible. The complexion of our president, the number of women who serve as Justices on the Supreme Court, the broad support for Medicare, the availability of curbside recycling, the social sanctions associated with bullying or cigarette smoking all reflect social and political changes only a few visionaries could have imagined 50 years ago.

And progress on any issue forces us to see just how much more there is to be done.