It might be justifiable to arm the rebels if that were only way to achieve the humanitarian objectives of the intervention. Yet there isn’t any evidence that it would be necessary to do so to defend Benghazi as a sanctuary. It seems clear that Benghazi can be defended from the air by NATO, even if that requires enforcing “no-drive” zones occasionally. That may be expensive and the aerial operations may last longer than American or European publics might wish, but if those are the decisive points then the intervention should not have been undertaken in the first place and Benghazi’s civilians should have been left to their fate; the high cost and indefinite duration of the aerial intervention was completely predictable. It cannot be policy to protect the lives of tens of thousands of Libyan civilians only if the intervention meets certain standards of cost effectiveness from week to week…

There is time to try to force out Qaddafi by enforcing the no-fly, no-drive zone; enforcing sanctions; and increasing the political pressure on his regime. If it is really necessary to do something more ruthless in order to overthrow him in a timely way, then it would be better to use the elasticity of the U.N. resolution, and the cover of air strikes, to target precisely culpable regime commanders or facilities the Libyan leader values, while quietly communicating ultimatums to Qaddafi and his sons. Precise NATO bombing in Belgrade during the Kosovo conflict persuaded Slobodan Milosevic to give up a lot faster than the operations of the Kosovo Liberation Army ever would have—and the K.L.A. looked like the Wehrmacht in comparison to the rebels who have been racing up and down Libya’s highways in recent days.