Contrasting Barack to past campaign successes is a little bit of apples to apples there. What's more important is what Obama's doing right versus Gore and Kerry (and technically Dole and Bush, but their biggest mistakes were basically running against Bill Clinton). I wouldn't categorize either of the past failures as "childish", per se... Kerry was a douche, but he was a grown-up kind of douche, and Gore never even displayed any desires or emotion, much less let them get out of control.
I think the main thing is that Barack comes off as a real, genuine Mister Smith kind of politician, even if we all know he's not that idealistic or when we disagree with his values. People truly, generally are willing to place their trust in the guy, which is something that nobody in American politics has warranted since... long before any of us were born. Clinton maybe got 50%, but he betrayed that whenever he could. Point is, I've never heard this race described as "The Lesser of Two Evils" or anything like that - it's pretty black and white now. And, er, we like the black.
