Barack Obama made history yesterday, when he told an ABC News reporter that same-sex couples should be allowed to marry. Marriage equality activists have had a rocky history with the President, who repeatedly shunned opportunities to do the right thing – and only recently admitted that his views on the issue were “evolving.” Obama chose to make this announcement less than 24 Hours after North Carolina voters – in a swing state his campaign views as crucial in November – passed by a solid majority an anti-gay marriage amendment, which made the news even more remarkable. But credit goes to the gay rights movement who refused to take “no” for answer – holding the President accountable that made yesterday’s watershed moment possible. And after Vice President Joe Biden endorsed gay marriage on Sunday, the groundswell became too much for Obama to sit on the sidelines.

Much to the chagrin of progressives, Barack Obama has proven time and again to be cautious to a fault – and often reluctant to put up a fight. As the President himself admitted in 2006, “by nature I’m not somebody who gets real worked up about things.” And there will no doubt be cynics who believe that this was a calculated decision to rally up the base for his re-election – in a effort to bridge the “enthusiasm gap.”

But the best way to understand what led to yesterday’s moment was how the LGBT community has been able to move this President – more so than other progressive constituencies. Simply put, they did not cow down to political fears that attacking a Democrat in the White House will “embolden” Republicans, they do not trade access with results – and they know that only by complaining loudly will they respect us.

After the Obama Administration defended DOMA in 2009 with legal arguments equating gay marriage with pedophilia, a group of gay bloggers organized a boycott of the D.N.C. called “don’t ask, don’t give.” A few months later, the Justice Department reversed themselves – after claiming they were bound to simply “defend” the law.

Frustrated by the Administration’s slow response on Don’t Ask Don’t Tell, Lt. Dan Choi and others chained themselves to the White House. It caused such a stink that repeal became a reality in late 2010, despite Democratic leaders urging advocates for months to “wait” until the President’s second term. As John Aravosis noted last year: “the progress that has been made is when we have been a royal pain in the ass. We don’t get what we want because we don’t stand up to him enough.”

On gay marriage, I had always assumed we would get more favorable results from Obama if we started proving our political power by winning at the ballot box. Which is why Prop 8’s passage inevitably delayed the fight to repeal the Defense of Marriage Act – and after we lost Maine in November 2009, Obama made a sharp right turn. When Amendment One in North Carolina passed on Tuesday – though not unexpected – it did not bode well for our prospects at being taken seriously.

Which is what makes the President’s decision – on the day after North Carolina – so much more remarkable. With the Democratic National Convention in Charlotte, and Obama’s re-elect team viewing North Carolina as a top priority, the cautious money would have been to stay out of it. But these things don’t just occur in a vacuum.

After months of activists hounding the President on marriage equality, the final trigger was Vice President Joe Biden’s appearance on “Meet the Press” last Sunday. Biden, with his tendency to shoot from the hip, responded that he was “absolutely comfortable” with same-sex marriage – prompting progressives to react with joy.

The Obama White House immediately went into damage control mode – saying the Vice President “really wasn’t saying anything” that Obama had never said before. But they weren’t fooling anyone outside the Beltway, and the New York Times editorial on Monday was brutal. Now, even the White House has admitted that Joe Biden “forced his hand” on marriage equality, when he had planned on coming out publicly a lot later.

Biden’s statement may have been the final trigger, but the LGBT movement deserves the credit – despite the odds – to hold firm on getting the President to take this historic stance. And it’s a lesson that other progressive constituencies should take heart in, as we strive to make Barack Obama the President we hoped he would be.