It's a good question, and David Brooks offers a perceptive psychological explanation today. Obama, Brooks argues, is a peripatetic, picaresque character, migrating from one place to another and from one institution to another without ever fully belonging to any. This disconcerts those voters who like their leaders rooted. And maybe David's onto something. As a geographically transplanted founding member of the post-boomer meritocratic elite, I'm not the most objective observer here. There may also be residual race-consciousness at work or simply guardedness about Obama's relative Washington inexperience.

But I'd add two more factors to the mix. The first is Iraq. The swift decline in violence and chaos there has changed the debate from purely how to get out as swiftly as possible and cut our losses (or sustain a grueling endless conflict) to what are the costs and benefits of staying longer or leaving sooner, and the tactics of each option. Obama's candidacy soared in response to a foreign policy catastrophe all his serious opponents supported at the start. The catastrophe endures, of course, and the financial costs of continued enmeshment grow all the time. But the sharp decline in deaths of Americans has done what McCain needed: it has given the neo-imperial project a new lease on life. We are now told, for example, by three of the proponents of the war that we cannot even begin major drawdowns until 2010. And if chaos or unrest continue or increase by then, well, we'll have to wait some more, won't we? If the criterion for departure is a peaceful, unified Iraq, we could be there as long as the British once were. McCain's previous position was to hang in while Iraq continued to burn. His new position is to hang in and somehow turn a strategic blunder into a strategic success (even if no sane person, knowing what we know now, would have begun this thing in the first place). This is a much, much better place for McCain to be than he was just five months ago. Still not great; but no longer awful.