Iraq has nothing in common with Viet Nam. It will stand or fall on it's own, but it will never be another Viet Nam.
50,000 killed vs less than 1,000
limited rules of engagement vs free rein to perform military operations
2 countries vs 1
Military and logistical support from Russia and China vs none
Iraq is not Viet Nam, it may fail still especially if Heinz-Kerry gets into office, but it will stand alone on it's own merits.