In yet another attempt to be on both sides of a controversial issue, President Obama refuses to be straight about his position on gay marriage.

During the 2008 presidential campaign Obama said he did not support same-sex marriage and believed “marriage is between a man and a woman.” You can watch Obama say it here.

Two years later, on Oct. 27, 2010, Obama revealed that his views on gay marriage are evolving.

“I have been to this point unwilling to sign on to same-sex marriage primarily because of my understandings of the traditional definitions of marriage. But I also think you’re right that attitudes evolve, including mine.”

Last year Obama instructed the Justice Department to no longer defend the constitutionality of the Defense of Marriage Act, the legal prohibition on federal recognition of same-sex marriages.

Then, on Sunday, in an appearance on NBC’s “Meet the Press” Vice President Biden said that he is “absolutely comfortable” with gay couples having the same rights as heterosexual couples. On Monday Secretary of Education Arne Duncan said he believes gay marriage should be legal in the United States.

That got the White House press corps so hot and bothered that White House press secretary Jay Carney had to obfuscate president Obama’s evolving position on same-sex marriage more than 50 times during yesterday’s press briefing. Watch a video of Carney’s ordeal:

The reason Obama goes to such lengths to try and be perceived on both sides of the gay marriage controversy is simple –it is his politics of expediency.

Today Gallup reported that 50 percent of Americans believe same-sex marriages should be recognized by law as valid, with the same rights as traditional marriages. That’s down from 53 percent  last year.  Forty-eight percent say such marriages should not be legal. According to Gallup:

President Obama’s campaign strategy team obviously is continuing to grapple with how to handle it — with the vice president on the one hand essentially endorsing legalized gay marriage, while the administration on the other hand stops just short of the same pronouncement.

Two core Obama constituencies -– young voters and African-Americans — are on opposite sides of the gay marriage divide. Today North Carolina, one of this year’s critical swing states, is voting on a constitutional ban on gay marriage. So Obama, even more nuanced than Senator John Kerry, continues to try and be perceived as if he is both for and against gay marriage.