President Obama upended the debate over gay marriage on Wednesday, telling ABC News' Robin Roberts that he now believes "same-sex couples should be able to get married." (Watch the video below.) Obama, who previously supported recognizing civil unions but not gay marriage, said his views on the hot-button issue went through an "evolution" over several years as he talked to "friends and family and neighbors" and considered the issue in light of the gay "members of my own staff who are in incredibly committed monogamous relationships." How will Obama's shift affect the fight over same-sex marriage? Here, five consequences: 

1. It makes the presidential campaign more polarizing
After Vice President Joe Biden came out in favor of same-sex marriage on Sunday, followed by North Carolina's resounding approval Tuesday of a constitutional amendment banning it, the president no longer had the luxury of continuing his long period of evolution, says Ed Kilgore at Washington Monthly. Across the nation, support for gay marriage is "slowly growing" — a recent Gallup poll showed 50 percent of Americans want to legalize it — but remember, there's an "underlying dynamic of ever-increasing partisan and generational polarization" on the issue. As a result, Obama's clear stance will likely make the campaign even more divisive.

2. It hurts Obama in swing states
Obama's "cynical dithering" was getting old, says Allahpundit at Hot Air, and he was running the risk of losing big campaign donations from liberals if he didn't get off the fence. But that doesn't mean his campaign problems related to gay marriage are over. "The bolder he is in endorsing gay marriage, the bigger his headache with a whole bunch of swing states that have voted to ban" it — states like Florida, Virginia, North Carolina, and Ohio. It seems like Obama knows that. "His strategy now is simply to get it over with ASAP and then let people forget about it over the next six months."

3. It complicates things with black voters
This was a "calculated gamble" for Obama, says Chris Cillizza at The Washington Post, as he's making a principled stand that will help him rally the young voters he'll need to win. It also gives his fundraising base a reason to send more checks — 1 out of every 6 Obama donors is gay. But "if the LGBT vote is a pillar of Obama's base, the African American vote is an even bigger pillar." And "African Americans have consistently been one of the groups most resistant to gay marriage."

4. It puts Mitt Romney in a tough spot
Obama's gay-marriage endorsement will also make things uncomfortable for GOP rival Mitt Romney, says Maggie Haberman at Politico. Romney, who now opposes gay marriage after saying in his 1994 Senate race against Ted Kennedy that he supported full equality for gays and lesbians, does not want to "focus extensively" on this issue, which opens him up to the old flip-flopper charge. But he has to solidify his base, perhaps by repeating his call for a federal constitutional ban on gay marriage. And that could rattle the many independents who support gay marriage.

5. It won't change much — but the symbolism is powerful
It has long been an open secret that Obama supports gay marriage, says Doug Mataconis at Outside the Beltway. And while his public statements won't lead to any immediate legislation, "it's undoubtedly historic for an American president to endorse same-sex marriage." For the first time ever, Obama is putting the full moral force of the presidency behind the central civil-rights issue of our time. That's a pretty "important use of the bully pulpit."