On MSNBC, Russert says the Obama camp is convinced that the gas tax debate worked to their favor, in that it changed the subject from Jeremiah Wright to Obama's integrity. That would mean I was wrong and E.J. Dionne was right.
On the other hand, as the pundits obsess over tics in the campaign coverage, bear in mind that it's always possible that Obama simply swamped Hillary with paid advertising and all the organizational perks that come from having vastly more money to spend. (Which is not to take anything away from him--all in the game, as they say. And it's especially legit when your money is coming from millions of ordinary small donors.)
Update: A colleague not-so-gently reminds me that I need to eat crow and acknowledge that Noam and Jon Chait may have right, too (a few days before Dionne made his case). That's assuming the gas tax really was a winner for Obama, which still isn't totally clear.