President Obama has completed what he called his "evolution" on the issue of gay marriage. During an interview with ABC News on Wednesday, Obama openly endorsed same-sex marriage.

But while this decision will play well to an important part of his base, it also poses some risks for Obama in his re-election efforts.

Following Tuesday's election results in North Carolina, there are now 30 states that have constitutional amendments and/or laws banning same sex marriages.

These states combined represent a total of 309 electoral votes.

Perhaps more importantly, there are also seven critical battleground states among this group: Florida, Ohio, Virginia, Colorado, Pennsylvania, Michigan and North Carolina. These states account for 114 electoral votes.

To put that in context, that number alone is more than 40 percent of the 270 electoral votes a candidate needs to win the presidency.

Just because states have provisions barring gay marriage doesn't mean their voters would reject Obama in the fall on that single issue.

Senior administration officials, though, have told Fox News they simply don't know how Obama's endorsement will play, since this is unchartered territory for a sitting president.

Chief White House Correspondent Ed Henry contributed to this report.

 

Jake Gibson is a producer working at the Fox News Washington bureau who covers politics, law enforcement and intelligence issues.