I agree with everything Kaus says here (thanks to Ryan's Head for the link), so I'll just quote it in full:
If a man says he has a gun, acts like he has a gun, and convinces everyone around him he has a gun, and starts waving it around and behaving recklessly, the police are justified in shooting him (even if it turns out later he just had a black bar of soap). Similarly, according to the Duelfer report, Saddam seems to have intentionally convinced other countries, and his own generals, that he had WMDs. He also convinced much of the U.S. government. If we reacted accordingly and he turns out not to have had WMDs, whose fault is that? Why doesn't Bush make that argument--talking about Saddam's actions in the years before the U.S. invasion instead of Saddam's "intent" to have WMDs at some point in the future? (It wouldn't necessarily make the Iraq war prudent, but it would make Americans feel more comfortable about it than what Bush has been telling them.)
A couple things interest me especially about his comments and the articles he links to. First, the L.A. Times piece is the opposite direction from what I'd been hearing. It says Saddam Hussein was the only one who knew the status of his WMDs and that it wasn't everyone else's lying to him but rather his keeping everyone else from seeing the full picture that led so many people to think he had lots of WMD and active programs developing them en masse.
Second, the NY Times piece quotes Kerry is babbling about not going to war and then making up reasons after the fact. I challenge anyone to come up with one reason Bush added after the fact. All the major reasons were there in the arguments to the U.N.
Third, his main point is that Bush has the better case than Kerry but just isn't making it. That sounds dead right to me. I'm not sure Cheney even got this right, but he was closer to it. Plenty of members of the administration have seen this and said it publicly, including Condi Rice. Why don't they encourage him to say this? I don't think what he's been saying is wrong. The reality of the situation was dangerous enough to be worth taking action. It's just a much weaker argument than the one he has available to him. [Update 5:11 pm: Andrew Card was just on and making this argument, so maybe Bush is going to make it tonight. We'll see.]