Not getting our men out of Afghanistan as soon as Bin Laden was iced. That was the golden opportunity. Now he's continuing the failed nation building crap Bush started and making it even worse by "apologizing to the Afghan people" as our soldiers are gunned down by 6th century rioters. Karzai is the one who owes an apology.
This is the one act that Obama's done that truly disgusts me. Everything else is petty political crap.