True, but it is an awful admission of incompetence of command for the first five years. Furthermore, it is axiomatic--until Vietnam, that is--that a foothold is not secure if it is not held for good.
Indeed, it is embarrassing for the generals and the pentagon...but that has always been our problem. Our military complex is always busy training to fight the last war.
We used Napoleonic tactics (designed with inaccurate muskets in mind) with the first ever mass-produced rifles in the Civil War, resulting in almost 1 million casualties. It wasn't until the end of the war that both sides developed trench warfare to counteract the new weapon's lethal accuracy.
In WWI, we were good at the Trench warfare developed during the Civil War, but needed new combined-arms tactics to push past the massive European trenches (British Tanks).
In WWII, we had to pretty much invent, as we went along, amphibious and joint air-naval-land operations, because the battlefield had expanded to the Pacific and to the air.
In Korea, we started out using maneuver like we did against Germany in WWII with combined arms, but the overwhelming number of hostiles turned the war into a battle of attrition.
In Vietnam, we decided to fight an attrition war like we did in Korea, but the North Vietnamese were using guerrilla warfare in the jungle, something we just didn't prepare for.
Arguably the only time our doctrines initially matched the conflict was Operation Desert Storm, and with spectacular results! The air-power focused "Shock and Awe" dominated Saddam's soviet-era army.
Now, in the 2nd American-Iraqi war, we attempted to use Shock and Awe tactics when we needed a boots-on-the-ground counterinsurgency strategy. It took us 5 whole years to re-work the way our army functions to meet this task.
Considering that we only just recently have figured out what we need to do to make Iraq peaceful, should we not follow the direction of our generals in determining troop levels and re-redeployment dates? It would seem rather unwise, I think, to arbitrarily pull the rug out from under our soldiers, given they have just recently adopted the tactics that can pacify Iraq?