George Will has an answer, reprinted here from the last paragraph of his recent column:

“Such places are habitats of people who by now may be lightly attached Obama voters — people who like the idea of him but not the results of him. As Holman W. Jenkins of the Wall Street Journal astutely writes, “Obama’s great political talent has been his knack for granting his admirers permission to think highly of themselves for thinking highly of him.” Romney’s great political challenge is to wean them away by making them faintly embarrassed about their former infatuation.”

-JD Cross