As with John Edwards, Obama bases his entire candidacy on glamour and eloquence and emotion. Edwards could never adequately explain how he meant to close the gap between the "two Americas" he loved to talk about, and Obama has yet to define what he really has in mind (beyond higher taxes) with the "change" and "hope" he endlessly invokes.

With both candidates, there's a lingering suspicion on the part of many voters that we're really dealing with empty suits -- appealing packages, full of sound and fury, signifying....nothing.

There's also the sense that these are two guys who love to gaze longingly in the mirror, who are a bit too full of themselves, too cock-sure and glib and arrogant for their own good.

The fact that both men came from modest circumstances may help to explain their self-infatuation, but it doesn't mitigate its impact. During the primary campaign against Hillary when critics began to attack Obama for "elitism" and "arrogance" they weren't talking about an elite status based on financial resources or insider influence (even though Obama boasts both). They alluded, rather, to the smug arrogance of high intelligence, movie star looks, natural athleticism, Ivy League degrees, lucky breaks, and effortless success. All viable politicians possess robust egos --otherwise they'd never endure the ordeals of modern campaigning, obviously. But there's something about the Godzilla-sized self-love of Edwards and Obama that stands out, even in a crowd of conceited and presumptuous presidential wannabes, something that makes you long to take both men down a few pegs.

In the deepest sense, the Edwards explosion will hurt Obama because it reminds us of the core similarity of two charming, media-genic guys who believe that despite their lack of meaningful experience they are the only ones who can rescue the United States and represent "the change we've been waiting for."

There's no reason to believe that Barack Obama, with his well-advertised devotion to his charismatic wife, ever followed John Edwards' example in allowing his egotism to indulge extra-marital adventures. But even assuming an impeccable record of matrimonial loyalty, there's still an undeniable history of infatuation that imperils the Democratic campaign.

For Barack Obama, as with John Edwards, his most dangerous love affair is with himself.