Implicit in the Powell Doctrine was the assumption that the wars of the future would be large, uncertain, expensive and therefore infrequent. Implicit in Rumsfeld’s thinking was the expectation that future American wars would be brief and economical, all but eliminating the political risk of opting for force. Rumsfeld believed that technology was rendering obsolete old worries about fog, friction and chance. Why bother studying Clausewitz when Shock and Awe could make a clean sweep of things? For Rumsfeld and his coterie, this was the appeal of having a go at Iraq: a swift victory over Saddam would validate Rumsfeld’s ‘vision’ and discredit those who were obstructing his reforms. According to Cobra II, he was certain that a ‘rapid defeat of Iraq on his terms would break the spine of army resistance to his transformation goal once and for all.’...Once again: Complaints about how Rumsfeld didn't assign enough troops miss the point. Rumsfeld didn't assign enough troops not because he was incompetent - though he is - but because of calculation. If Iraq had been successful, Rumsfeld believed it would clear the way for future wars against Syria and Iran. Despite the deaths incurred because of Rumsfeld's stupidity, it is probably better for the world that he turned out wrong. Given the chaos that has emerged from their war on Iraq, the world would be a much worse place if the United States had waged war against Iraq, Syria, and Iran.
In the event, these assumptions proved fallacious, even with Saddam Hussein doing his best to help out: convinced that the US would never actually try to take Baghdad, Saddam concentrated on threats from Iran and from within Iraq itself; as a consequence, the Iraqi general staff had no plan worthy of the name to defend against an Anglo-American attack. When that attack began, the anticipated mass defection of Iraqi forces did not occur. The Iraqi army did fight, though poorly – and some US troops found even this level of opposition disconcerting. ‘Why would the Iraqis shoot at us?’ one army captain wondered to himself. ‘We are the good guys.’
Let me also just say that when someone is only restrained from unleashing massive military force because of the "political price" they may incur, that person is certifiably insane.