Todd Gitlin is right, of course, in suggesting to progressives currently giddy about polling trends in the presidential campaign that overconfidence is a bad idea in politics, as in any other competitive endeavor. And every Democrat of a certain age remembers past elections where we managed to snatch defeat from the jaws of victory.

But though Todd doesn't come right out and say it, I suspect much of his fear is from the most immediate bad memory: Election Night 2004, when many of us were half-convinced we'd already won a week or so out, and then, on reading those first exit polls, threw caution to the win and declared victory.

It's important, though, to remember why those expectations turned out to be unrealistic, and distinguish caution from superstition.

In the home stretch of the 2004 campaign, expectations of victory among progessives were partly attributable to a projection of our own belief that George W. Bush was a failed president pursuing failed policies which no reasonable person could support. We rationalized the terrible midterm election results of 2002 as an aberration attributable to the proximity of 9/11, and whatever we thought of John Kerry (I happened to like him a lot), figured he was a sufficiently acceptable candidate to harvest the inevitable backlash against Bush.

On a more analytical level, the factor many of us fixated on was the political science truism that undecided voters in the late stages of a campaign tend to break decisively against incumbents, particularly if they are sour about the condition of the country. With undecideds exhibiting very high levels of "wrong track" sentiment at this point four years ago, the thinking was that Kerry would win if he could keep the contest close in the polls, which he did. And that's why those flawed early exit polls had many of us calling friends and relatives and fatuously urging them to ignore the red tide on their television screens, because we had actually won. We were predisposed to ignore adverse evidence, even in the face of actual returns.

Sure, there are three weeks to go in the current campaign, and weird stuff can still happen. But unless you believe in the Bradley Effect (which as Todd notes, is mostly a myth or an anachronism), or really do think the GOP can contrive a terrorist attack or get away with voter suppression or vote-stealing on a vast scale, the situation for Democrats is undoubtedly better than it was in 2004. Polls aside, the "fundamentals"-- including the issue landscape, party ID and registration trends, the unprecedented levels of unhappiness with the incumbent, and the political impact of the economic crisis--are decisively better. And even if you don't drink every drop of koolaid about Obama's "ground game," I don't know a single person in politics who thinks McCain's operation is superior to Obama's. That's totally aside, of course, from the dynamics of the campaign itself, wherein the central contradiction of the McCain candidacy--his effort to simultaneously pose as a supra-party "maverick" while bending to the conservative "base" on every major subject--is blowing up spectacularly almost every day.

Does that mean Democrats can or will start "coasting" and giving the GOP an outside chance to catch up? I don't think so.

We should focus relentlessly on the fact that there's all the difference in the world between a narrow Obama win and mixed "downballot" results, and a big Obama win with House and Senate gains that give Democrats an actual working majority in the former chamber, and a filibuster-proof majority in the latter. It could well be the difference between a successful and unsuccessful Obama administration, and its ability to reverse some of the more toxic Bush-Cheney policies. If you want to dwell on bad memories of elections past, save some mental space for 1994, when the Clinton administration''s early struggles contributed to a disaster that we are only now beginning to overcome.

Avoding irrational optimism is essential right now, but so, too, is avoiding a superstitious pessimism that could obscure the big challenges just ahead.