"I asked when was the last US victory in war." ===============================================================
harry...
Gulf War I comes to mind -- a stunningly swift victory.
But, you are over simplifying your question. The US has not been defeated militarily in war - the defeat has always been political, and come on the home front (especially for VietNam) where the anti-war groups (usually liberals) have eroded the will to fight. The same is about to happen once again in Iraq.