You have to also consider how the conflicts turned out, we left Vietnam with our tail between our legs. Iraq hasn't gone as swimmingly as it should have or we would have liked for it to have gone, but the end result (at least up until 2009) is looking much better than what happened to Southeast Asia after we pulled out.
Iraq and Vietnam are not equal travesties.
That's because we had a President who was willing to continue to press forward with the fight in the face of unfaltering criticism and personal attacks. Vietnam was always fought halfhearted, with no real strategy other then to keep a war going. LBJs fault was not fighting the war to win but to pass the buck on to the next lucky sap to get elected. Nixon really started fighting the war after his election but by that point the tide of popularity was against him and the wave of peaceniks and Congress was against him all the way. If the war had been fought like Nixon did from 64 onwards the US would have won or at least stabilized the situation.