I doubt that
I don't think the folks feel that way. They will not think he lied. They will think he was mistaken and it was a good thing anyway. If we had taken the 10,000 casualties that some of the radicals predicted it would be another story.
Maybe you are right but that's a fairly short term prediction and I will go out on a limb and say he will win handily if the dems make a major issue of no WMD. It will be the economy that gets Bush, if anything.