Anyway, the real issue here is how supporters of American foreign policy can address the perennial argument that America's record of immoral actions in the Cold War invalidates any aggressive initiatives the United States plans today...The reason for the "America supported Iraq then, and therefore shouldn't invade now" doesn't, in my view, have much to do with the moral culpability of the administration, but their credibility. Rather a lot of the rhetoric about Iraq relies on assurances by the Administration that they have evidence and reasons that for various reasons they can't bring to light, but that they should be trusted to have. This whole point basically boils down to "why on earth should we believe you, and why on earth should we trust you to do it properly and improve the situation"? (Assuming, for the moment, that the silly argument that "it can't get any worse" is rightly ignored; it can get worse, very much so.)
I think the proper response is to admit what the US did wrong and shift the discussion to the merits of its current policy. As Ken Pollack tells the WaPo, what we did in the 1980s "was a horrible mistake then, but we have got it right now."
Sure, everybody would like to see Saddam gone, but the question is whether or not an American invasion is the right thing. That is a harder question, and the one that this whole thing strikes at. To say "no, really, we've got it now" is to invite the question "what if you're saying the same thing ten years from now?" It's a legitimate question, and one that remains to be answered.