Some leading conventional-wisdom meisters, like Time's Mark Halperin, like to say that this race is completely about Obama. When they say that, you can hear them setting themselves up as Obama's judge and jury, just waiting for him to trip up so they can say that he's failing to "close the deal" and there are just "too many questions" about him, as they nudge their readers toward McCain, a media darling for many years now.
I think Tomasky is probably going a bit too far with his suggestion that the "it's all about Obama" notion is intentionally designed to help John McCain. But he does have a point. Any election is equally about the two candidates. There's no point in measuring one candidate except in the context of comparison with the other.
Now, it's probably true as an empirical matter that the public's perception of Obama matters more than its perception of McCain -- people want a Democrat to win, and Obama just has to make himself acceptable in order to win. But I think lots of reporters and pundits have internalized this notion to the extent that they are covering the race as if it's a simple up-or-down vote on Obama. Hence the intense focus on Obama's relatively modest ideological repositioning and total lack of attention to McCain's massive rightward shift.
I don't think this is a ploy designed to help McCain, but I do think it has that effect. After all, if Obama does not pass the threshold of acceptability, then we'll have a President McCain. The voters should weigh what that would be like, too.
--Jonathan Chait