Much has been made of comparisons between Iraq and Vietnam; quagmires from which we cannot emerge with honor and respect intact. I see two commonalites:
President George W. Bush, Vice President Dick Cheney, Secretary of Defense Donald Rumsfeld, and General Tommy R. Franks have no more business running this war than did President Lyndon Johnson (who I believe would rank high in the pantheon of American presidents had it not been for Vietnam), Secretary of Defence Robert MacNamara, Secretary of State Dean Rusk, and General William C. Westmoreland in running theirs. Just as the 1960s quartet massively screwed up their war, this quartet has screwed up this one. I'll leave the question of justification for the wars for another time. For now, I'll simply say that mistake has piled on mistake, has complicated mistake until the situation may well be beyond redemption.
The biggest mistake we made early on in Vietnam was insisting that the South Vietnamese government operate on the same principles and in the same manner that the American government does. South Vietnam had no tradition of democracy; only tyrants, kings, and strong-men; South Vietnam couldn't function as an American-style democracy, particularly not in the middle of a war in which it was fighting for its very survival. It is sheer folly to expect Iraq, which likewise has no tradition of anything even remotely resembling democracy, to start up an American-style democracy and make it work right off the bat.