In the lead-up to the war against Iraq, liberal doves all made pretty much the same point, with some variation: However successful the conflict itself might be, the long-term diplomatic costs of alienating much of the world would outweigh any benefits. This prediction, while questionable, at least had the benefit of playing out over such an extended period of time that it could not be conclusively disproved until its adherents were all long dead. Alas, after the campaign hit a snag, many doves were unable to resist the temptation to crow over the supposed overconfidence of the war plan -- and as a result looked silly a few days later when Saddam Hussein's regime collapsed, to the apparent delight of most Iraqis.

Now, it seems, war opponents are making a similar mistake. The present cause of their crowing is the failure (thus far) of the military to find solid evidence of weapons of mass destruction. Opponents of the war are starting to assert, or at least hint, that the entire rationale for the conflict has been undermined. The notion that Bush made the whole thing up about weapons of mass destruction has taken root on the left and is creeping ever closer to the liberal mainstream. My fellow liberals who have taken up this line are once again making a disastrous misjudgment.

The soft version of this argument is that the delay in finding weapons of mass destruction proves we should have given the U.N. weapons inspectors more time. Hans Blix intimated as much when he archly noted that "it is conspicuous that so far [U.S. troops] have not stumbled upon anything, evidence." The reason U.S. troops haven't yet found anything is that Hussein worked assiduously to hide his proscribed weapons. Iraq moved weapons around the country in tractor-trailers, buried them in out-of-the-way places and so on. The lesson is that finding Hussein's weapons isn't as simple as pulling over to the side of the road and peering into suspicious-looking buildings. It requires cracking open the elaborate secrecy apparatus surrounding them. That's something Blix was never going to be able to do. The difficulty of locating weapons of mass destruction doesn't prove that inspectors should have been given more time. It proves that inspections could never have worked while Hussein remained in power.

Recently a more radical version of this argument has gained credence: Maybe there never were any such weapons. In this view, the entire notion was a kind of Gulf of Tonkin redux -- a sinister ploy by Bush and his neoconservative minions to whipsaw the public into supporting a war whose real motives (Israel? Oil? Empire?) could not be stated openly. It's entirely appropriate to question the honesty of Bush's stated rationale for fighting. After all, the arguments he uses to justify his domestic agenda are shot through with deceit. (Consider his shifting, implausible and contradictory justifications for cutting taxes.) And it's also true that a few elements of the administration's evidence against Iraq have turned out to be overstatements or outright hoaxes.

So Bush's claims should never be taken at face value. But accepting the fact that Iraq had an extensive and continuing program for weapons of mass destruction doesn't require taking Bush at his word. The U.N. Special Commission, when it finished its work in 1999, concluded the same thing. So has Germany's intelligence service. So has the United Kingdom's. Indeed, the only people who seem to doubt it are either allies of Hussein or those who distrust Bush so much that they automatically assume everything he says must be false.

Perhaps the most disheartening development of the war -- at home, anyway -- is the number of liberals who have allowed Bush-hatred to take the place of thinking. Speaking with otherwise perceptive people, I have seen the same intellectual tics come up time and time again: If Bush is for it, I'm against it. If Bush says it, it must be a lie. Their opposition to Bush has made liberals embrace principles -- such as the notion that the United States must never fight without U.N. approval except in self-defense -- to which the Clinton administration never adhered (see Operation Desert Fox in 1998, or the Kosovo campaign in 1999). And it has made them forget that there are governments in the world even more odious and untrustworthy than the Bush administration.

The writer is a senior editor at the New Republic.