If I'm not mistaken, General Westmoreland asked for more troops in 1968, he was denied.
Granted Iraq and Vietnam are both different wars, but the one thing they had in common is that both wars are unpopular. Even if we are on the verge of winning it all in Iraq, the Democrats may call it quits.
By the way, I believe that the Iraqi Parliament is in recess for the month of August, despite that they still have a lot of issues to work on and we are losing patience in Washington D.C.
You are correct that we are in a very critical time for the was in Iraq, and things could still go either way. General Westmoreland didn’t get the troops he wanted (even though US troop strength in Vietnam peaked in September 1968 at 537,000), but even as the last US troops came home in January 1973, we had bombed the North Vietnamese into submission and a peace agreement followed. It was only when Congress cut off aid to South Vietnam in 1974 (and the USSR expanded aid to the North) that the Communists gained the upper hand.