When Edwards left the race, Clinton and Obama picked over aspects of the Edwards campaign message like grannies at a rummage sale. Obama finally, officially donned that fluffy "message of hope" wrap he'd had his eyes on since 2004, while Clinton coldly snatched up the abandoned class card. Then they condescended to sign Edwards' pledge to Tawk About Povuhty in 2009, and left.
Clinton came away wielding both the gender and class cards, and she began to ply them against that strange class of heroes called the superdelegates (set up to be faster than a November ballot, more powerful than the local yokels, and able to leapfrog future McGoverns in a single convention). She cited poll and primary results to portray herself as the more diverse candidate now. She even dared to challenge Obama's race-card defense by arguing hers is the broader coalition, since it includes working-class families and whites, both alienated by Obama.
Nevertheless, by all accounts Clinton has not succeeded. Strong testimony it is to the power of the race card in Democratic politics that a gaffe-tastic, platitude-prone naïf has prevailed against not just your ordinary Democrat backed by gender and class, but a Clinton.