Sealed Fate
Speaking of the obvious, Ambassador L. Paul Bremer, administrator for the U.S.-led occupation government until the hand over of political power on June 28, is now saying the US made two critical mistakes in Iraq (see the article here): "not deploying enough troops in Iraq and then not containing the violence and looting immediately after the ouster of Saddam Hussein."
Both errors are based on political decisions and both are rooted in the same problem. The Bush administration was warned that it would take hundreds of thousands of troops to execute the mission ordered of it. This is on the record and the spin doctors cannot deny it (although, as usual, the Bush administration used a whispering campaign to impugn the integrity of the general that had the cajones to tell the truth. You can bet no other general, who wants to stay in the military, will now do so).
But the politicians in Washington, looking perhaps towards the coming election, decided it would be political suicide to send such a large force. Why? Because the present military is not designed for a large scale, long-term mission. It's a light reaction force meant to put out so called "brush fire" conflicts. In order to have hundreds of thousands of troops in the field, for years at a time, would require the re-institution of the draft.
Politics being what it is, re-instituting the draft, without the justification to do so nor the support of US citizens, would mean the end of the Bush administration. So, for the politicians, the path was clear. No draft and therefore no hundreds of thousands of troops. Once that decision was made, the fate of the war was sealed.