With Libya, humanitarian hawks have found an almost too-good-to-be-true vehicle for this vision. In Qaddafi, the U.S. has an operatically villainous adversary who not only has the blood of Americans on his hands but also the blood of his own citizens, having pledged to Libyans who dare oppose him that his military “will find you in your closets.” From a purely ­Realpolitik perspective, Qaddafi also gives the U.S. a Muslim foe who—unlike even Saddam Hussein—is not particularly beloved by the Arab street, much less Arab leaders. Which explains why, unlike the war in Iraq, this military intervention is truly multilateral.

Then there’s the reality of this particular moment. There is no chance of the U.S. intervening militarily on behalf of the revolts in places like Bahrain or Yemen or Syria, where the U.S. either counts on the cooperation of its repressive leaders or fears the relative might of its armies. But Libya, with its isolated, intransigent dictator and ragtag military, presents no such difficulties. As such, it offers an ideal vehicle to signal to “those kids” (as an Obama aide, speaking to Politico, referred to Arab pro-democracy demonstrators) that the United States is on the right side of history.