This article summarizes the status of studies of Iraqi civilian casualties since the U.S. invasion. Best guess is that the number of war dead is in the several hundreds of thousands.
I accept that sometimes to defend ourselves there will be civilian deaths. But what I have said, and emphasize again, the United States that I believe in must have a damn good reason to kill people, especially civilians, and in Iraq there was no such reason. Explanations for the war range from a war for oil to a need to demonstrate to "the evil axis" that America would act, to a need to win in the 2002 midterm elections. When I think of multitudes of Iraqis killed for these reasons I am sick, and angry, and want Bush and Cheney tried for war crimes.