There are singular moments in U.S. presidential campaigns at which the fortunes of a candidate can turn one way or the other, never to be reversed.

In 2008, it was when John McCain, just after Lehman Brothers collapsed, made the bone-headed comment that “the fundamentals of the U.S. economy are strong.”

In this year’s election, that moment might have come today, when Mitt Romney issued a shoot-from-the-hip (and largely incorrect) criticism of the Obama administration in the wake of the attacks on U.S. interests and personnel in Libya and Egypt.

Romney is getting pounded for this by people on both sides of the political aisle, and I’m not sure he can recover.