Jon makes a lot of good points on the subject of whether Barack Obama would be in a stronger position for the general election if the Democratic primary hadn't dragged on so long. There are, of course, rebuttals to many of them: Yes, Obama raised more money than he probably would have otherwise, but he had to spend it running against Hillary Clinton rather than John McCain. And no doubt some of the tens of millions of Democratic dollars that Clinton raised after the nomination was all but arithmetically out of reach would otherwise have gone to Obama, so that it might have been spent building him up rather than tearing him down. Moreover, the "rumors" that Clinton would keep running until the convention weren't some feverish, paranoid vision on the part of Obama supporters; they were based on the fact that people inside the Clinton campaign said that they were considering staying in until Denver. (And, indeed, the few days Clinton spent "weighing her options" after Obama clinched suggest that they were doing just that.)
But my main disagreement with Jon's case revolves around this graph:
And one more thing: It looks like most of Clinton's supporters will, indeed, come around and support Obama (as they should!). But imagine if party elders and the pundits had somehow brought the race to a premature close. My bet is that a lot of her backers would be far more bitter now--and Obama would find himself with a more lasting, and more serious, problem among these voters.
This is true enough, I suppose, but it's the wrong counterfactual. Sure, there were some people who argued that Nancy Pelosi and Harry Reid and Al Gore and the ghost of JFK should all have come out and "forced" Clinton out of the race. (Whatever that means; it's hard to envision how such an effort might have succeeded, which is presumably one reason it never took place.) But the overwhelming criticism was not of party elders but of Hillary Clinton, for not bowing out graciously when it was clear she would not win a majority of delegates. (People differ on when exactly this was, of course, but by any reasonable estimation it was well before June 3.)
I agree with Jon that most of Clinton's supporters will come around and support Obama in the general election. But insofar as some of them remain bitter, it's overwhelmingly because Clinton stoked their bitterness in March and April and May, by arguing that Obama was an unfit commander-in-chief who didn't care about the white working class; by using a variety of dubious metrics to claim that she, rather than he, was the legitimate "winner"; and ultimately, by suggesting that the only reason she didn't grasp the nomination was sexism.
Yes, there are ways in which Obama may have benefitted from the extended primary--the remission of the Jeremiah Wright controversy certainly looks like one at the moment--but had Clinton bowed out earlier I think there's little doubt that there would now be a great deal less anti-Obama bitterness among her supporters.