Former ambassador to Croatia Peter Galbraith says that two months before the U.S. invaded Iraq, George W. Bush did not know that there were two major sects of Islam in Iraq. According to Galbraith, a year after giving his "Axis of Evil" speech, Bush met with three Iraqi Americans, who described to him what they thought the consequences might be if Saddam Hussein were taken out of power.
According to Galbraith, it became clear to them that Bush had no clue that there were Sunnis and Shiites in Iraq. The Iraqi American consultants explained the situation to him, and his response was: "I thought the Iraqis were Muslims!"
No one should be surprised. During the 2000 presidential campaign, Bush could not identify the Taliban. But as he himself has said--it's hard work, being president.