9/11, an inside job by the CIA carried out by Saudis, having nothing at all to do with goat herders in rural Afghanistan. Iraq was nearly as disastrous but much less embarrassing because the US didn't get completely kicked out (yet, at least) and the Iraqis managed to have a civilization both before and after the war. Afghanistan is the most embarrassing war because it's like a whole platoon of marines getting beat up by one scrawny drug-addicted bum.