David Broder, as many others have observed, noted the rough time Barack Obama has had of late:

Obama limped into the nomination as a vulnerable and somewhat diminished politician. After winning 11 primaries and caucuses in a row, his magic touch seemed to depart him. He lost the knack of winning the heart of the Democratic coalition, working families that look for help in meeting the economic challenges of their everyday lives. White, Hispanic, middle-aged or older, they had strong associations with Clinton and many questions about the commitments that lay behind Obama’s sweeping, reformist generalizations.

But the problem, Broder suggests, is not a demographic disconnect but a leadership vacuum:

What Democrats are just beginning to figure out is that John McCain is positioned to compete with Obama for the votes of the many Americans who are eager to put the hyper-partisanship of the past eight years behind them and witness a Washington that finally begins to address the nation’s challenges.But anyone who is realistic must recognize that forging fresh agreements in Congress and the interest-group-dominated capital will take an exceptionally strong president. Since early March, Obama has not looked like that president.

If Broder is correct, then the problems Obama faces are not merely “the Appalacian states don’t like him” or “Older women are mad,” but something more fundamental. Obama has, it seems, almost shrunk from view. The storyline each week has been Hillary Clinton’s wins, the atrocious demographic divide and the latest effort by Obama to tell us what he is not (e.g. a cohort of Reverend Wright, a naif in foreign policy, a question mark for Jews).

But the qualities we look for in presidents — the ability to command the stage, to shape the agenda, to rebut criticism with good humor, and to give citizens a sense of security — has been missing. Indeed, it has been backwards: the Democrats, the media, and his supporters have been trying to figure out how to protect him and carry him over the finish line. (The media coddling has, of course, gone on all year, but its intensity and unseemliness has increased as his perils became greater and his losses piled up.) Presidents aren’t supposed to be protected– they are the ones who protect the country.

And as to Broder’s point about John McCain, it is through sheer happenstance, I think, that the Republicans stumbled on someone suited to carve an independent image and deflect the damage to the GOP brand. To be frank, McCain won in spite of, and not because of, his maverick and iconoclastic views and attitudes. Conservative Republicans still bristle that he gives them too little respect. That very quality is now his ticket to competitiveness in the general election. Remember the Mitt Romney ad depicting McCain as the Democrats’ best friend? McCain could practically run that as his own ad in the general election.

So how did the Democrats manage to come up with such a vulnerable candidate and the Republicans a viable one? Sometimes there is such a thing as dumb luck.