From an emailer to The Corner:
More troops doesn't necessarily translate into immediate improvement. Sometimes it's how you use the number of troops you already have that makes the difference. In Lewis Sorley's A Better War, when Creighton Abrams stepped up to take over for the departing Westmoreland, he was offered more troops by LBJ. Abrams turned Johnson down, saying he would make better use of the troops he had on hand. He certainly did, as Sorley shows, with the successful Cambodian incursion and the switch to an emphasis on pacification and training the ARVN, along with clear and hold, versus Westmoreland's search and destroy strategem, using only US troops. This explains ARVN's better performance in the 1972 Easter Offensive, which threw back a conventional invasion by the North Vietnamese Army (The ARVN, US advisors and firepower were important to the victory, not US troops).
I think we're doing better in Iraq vis-a-vis Vietnam's ARVN. We started training the Iraqi Army early on, and we're doing better at it, while in Vietnam we started full-on training of the ARVN late in the game, after Abrams took over. But by then it was too late. So it's a plus for our efforts that we recognize that training and use of the Iraqi Army in the war is an important priority.
Also, with all this talk of withdrawing and other options, nobody seems to realize that it practically takes a decade or so to decisively win a counterinsurgency. The Malayan Emergency, which was fought from 1948 to 1960 by the British and the natives against native Communist guerillas, took over a decade before the British won it. We were in Vietnam for the 1960s before Abrams finally started producing some success, which as I've said up there was too late for any hope of victory. The Phillippine Insurrection also took a few years to win too; same with the US Marines in the Banana wars in the 1920s.
Going into the Iraq war as a supporter, I always knew it'd take that long to produce results like Abrams in Vietnam and the British in Malaya. I suppose that's why I'm more patient than most supporters of the war nowadays. If we do somehow lose Iraq, it'll be because we didn't realize that Iraq would take a decade, give or take one or more years, to stabilize.
P.S. - Westmoreland's strategy actually did kind of work (note that I did say "kind of"), though it isn't a favorite strategy of mine nor what we should use in Iraq. Hanoi admitted years after the war that they'd lost 1.5 million troops, meaning we actually bled them white, and a few more years (as in 1972-1975) of commitment would have knocked them out of the war. I'm assuming the enemy in Iraq has a smaller pool of manpower compared to North Vietnam's during the Vietnam War. I suggest drawing your own conclusions instead of taking this at face value, but I'm willing to bet that by year 6 or 7 (2008/2009) the enemy will barely offer much resistance. It'll (Iraq) start looking like Afghanistan then.
But that all depends on our willpower and how we use our troops and the Iraqi troops.