The Politico's Ben Smith reports from the latest Democratic debate:
Obama, like Clinton and Edwards, was unable to explain his opposition to same-sex marriage in principled terms, referring to it as a matter of "semantics." Obama cast his opposition as a matter of strategy and priority—he would not have advised the civil rights movement to make the repeal of anti-miscegenation laws a top priority in 1961, he said.
Clinton called her opposition "personal," but didn't explain it. And Edwards took back an earlier comment that his "faith" had led him to oppose same-sex marriage—but didn't elaborate on the source of his current opposition.
"Their reasons for opposing equality in civil marriage tonight became even less clear," Human Rights Campaign President Joe Solmonese said in a statement after the debate.
It's times like this when you gotta admire the forthrightness of Ted Kennedy, who, in reference to the Marriage Protection Amendment, thundered, "A vote for this amendment is a vote for bigotry, pure and simple."
Rob Bluey goes into more detail here.