If you want to know why Barack Obama is not trampling John McCain in the polls despite the pathetic state of the GOP - assuming you don't simply blame his numbers on racism, as do some commentators - look no further than a New York Times article Monday that tries to decipher Obama's deepest political instincts.

No one doubts that Obama's legislative record is liberal - often very liberal. But voters naturally wonder whether that's the final word on how he'd govern as president. Is he pragmatic or doctrinaire at his core? Is he someone who would wield executive power as a compromising realist or push policy relentlessly to the left?

Does Obama seek out opposing views and listen to them?

The Times puts an attractive gloss on Obama's political philosophy, portraying him as a complex realist who "carries in his intellectual DNA many of the tensions between the left and the middle in American political culture," to quote Peter Dreier, professor of politics at Occidental College. Yet the article as a whole seemed remarkably unsure on this score.

If Obama is a "visionary minimalist" who respects the deeply held views of those he disagrees with, as University of Chicago law professor Cass Sunstein believes, many swing voters will be reassured. (So will many who'll vote for John McCain.) But is he? And if so, why does he have so much trouble citing instances when he has defied his party or reached across the aisle to forge major legislation?

When asked about his bipartisan credentials at the recent Saddleback Forum, Obama pulled up lame. He'd "worked with John McCain" on "the issue of campaign ethics reform and finance reform," he said. But as Newsweek reminded readers, "In fact, the two worked together for barely a week, after which McCain accused Obama of 'partisan posturing' and added, 'I won't make the same mistake again.' "

One reason Obama is not trampling McCain in the polls is that voters wonder, reasonably, about the gap between his rhetoric of a new politics and his actual partisan record. Does the clash suggest a change of direction by the man or old-fashioned insincerity - or, for that matter, something else?

The third possibility? "He is not rooted in the way of a lot of politicians," Columbia University historian Alan Brinkley told the Times. "We don't know what his precise philosophy will be."

For some, that may be the most unnerving prospect of all.

Vincent Carroll is editor of the editorial pages.