The White House's continuous hinting that they really, truly, in their heart of hearts, support gay marriage is among the more ridiculous subplots of the 2012 election.
The strategic justification for it is that, sometimes, it's better for the president to let the people get there on their own rather than forcing the issue and losing — an event that can set movements back years, if not decades, as politicians become skittish long past the point that the danger has actually passed.