After Barack Obama's defeat in Pennsylvania, David Axelrod, his campaign manager, brushed it off: "Nothing has changed tonight in the basic physics of this race."

He may well be right -- but what a comedown. "Yes, we can" has become "No, she can't."

This wasn't the way things were supposed to play out.

Obama was supposed to be a transformational figure, with an almost magical ability to transcend partisan differences and unify the nation. Once voters got to know him -- and once he had eliminated Hillary Clinton's initial financial and organizational advantage -- he was supposed to sweep easily to the nomination, then march on to a huge victory in November.

Well, now he has an overwhelming money advantage and the support of much of the Democratic establishment -- yet he still can't seem to win over large blocs of Democratic voters, especially among the white working class.

As a result, he keeps losing big states. And general election polls suggest that he might well lose to John McCain.

What's gone wrong?

According to many Obama supporters, it's all Hillary's fault. If she hadn't launched all those vile, negative attacks -- if she had just gone away -- his aura would be intact, and his mission of unifying America still on track.

But the attacks from the Clinton campaign have been badminton compared with the hardball that Republicans will play this fall. If the relatively mild rough-and-tumble of the Democratic fight has been enough to knock Obama off his pedestal, what hope did he ever have of staying on it through the general election?

Let me offer an alternative suggestion: Maybe his transformational campaign isn't winning over working-class voters because transformation isn't what they're looking for.

From the beginning, I wondered what Obama's soaring rhetoric, his talk of a new politics and declarations that "we are the ones we've been waiting for," would mean to families troubled by lagging wages, insecure jobs and fear of losing health coverage. The answer, from Ohio and Pennsylvania, seems pretty clear: not much. Clinton has been able to stay in the race, against heavy odds, largely because her no-nonsense style, her obvious interest in the wonkish details of policy, resonate with many voters in a way that Obama's eloquence does not.

The question Democrats, both inside and outside the Obama campaign, should be asking themselves is this: Now that the magic has dissipated, what is the campaign about? More generally, what are the Democrats for in this election?

That should be an easy question to answer. Democrats can justly portray themselves as the party of economic security, the party that created Social Security and Medicare and defended those programs against Republican attacks -- and the party that can bring assured health coverage to all Americans.

They can also portray themselves as the party of prosperity: The contrast between the Clinton economy and the Bush economy is the best free advertisement that Democrats have had since Herbert Hoover.

But the message that Democrats are ready to continue and build on a grand tradition doesn't mesh well with claims to be bringing a "new politics" and rhetoric that places blame for our current state equally on both parties.

And unless Democrats can get past this self-inflicted state of confusion, there's a very good chance that they'll snatch defeat from the jaws of victory this fall.