I’m skeptical, personally, that the Egyptian military could have banned the Muslim Brotherhood without facing widespread civil opposition, and possibly worse. When Frum says some in the Obama Administration thought it was “preferable to live with [the Islamists] than to do what was necessary to resist them” that “what was necessary” could well have included supporting an outright military coup, and subsequent large-scale repressive violence. Meanwhile, the actual partial coup that took place has left military and civilian authorities jockeying for legitimacy, which is part of the background to provocations like the attack on the American embassy.
Drum is on the same page:
Conservatives too often assume that American power can accomplish anything we set our minds to. But it's not so. Sometimes there just aren't any good options, and the best path forward is to ride out the storm and refrain from doing anything foolish. It's not very satisfying at a gut level, but nine times out of ten it's the best you can do.