“He keeps reminding us that the best revolutions are completely organic,” the senior official said, quoting the president…

On television Mr. McCain has made similar points, and portrayed Mr. Obama as indecisive and weak. But curiously, in a sign of the uncertainties about how the politics of an American intervention would play out, few of the potential nominees for the 2012 Republican presidential ticket have expressed a strong opinion.

For the administration, Mr. Kerry’s view is more troublesome, given that he is a normally a strong ally on foreign policy issues. He was a fierce critic of the war in Iraq, but he sees Libya as a different matter.

He has pushed the White House to do more — including “cratering” Libya’s airfields so the planes cannot take off…

It is possible that the mere talk of no-fly zones had some effect. Pentagon and military officials confirmed that sorties by aircraft loyal to the Qaddafi government had dropped by half over the past three days. There was no explanation for the change; it could have to do with maintenance, or a decision to fly helicopters, which are less provocative and harder to track.