From a long New York Times magazine article by Jo Becker on President Obama’s reversal of the public position on marriage that he adopted during the 2008 campaign:
Caught between countervailing political forces, Obama called his top aides together and said that if asked again for his position, he both wanted and needed to drop the pretense and tell people where he really stood.
“The politics of authenticity — not just the politics, but his own sense of authenticity — required that he finally step forward,” [David] Axelrod said. “And the president understood that.”
But if he was really contemplating an endorsement of same-sex marriage, his advisers urged him to do it in a manner that caused minimal political damage.