Such zones basically favor the side with momentum, which two weeks ago were those opposed to Gaddafi. A no-fly zone placed atop Libya then would have frozen Gaddafi’s losing position into place and accelerated rebel efforts on the ground [bold mine-DL]. ~Mark Thompson

Er, no, not really. These zones favor the side that has superior forces on the ground, which is not the same thing as momentum. They don’t freeze a conflict into place or prevent one side from suffering sudden reverses. Most of what Gaddafi’s forces have achieved in the last week were the result of sustained rocket and artillery barrages on rebel positions, which was made more effective by the rebels’ poor defenses and lack of experience. A no-fly zone at any time over the last several weeks would have changed very little. Rich Lowry makes this point fairly well:

Indeed, the only thing worse than what’s happened over the last week or so on the ground is if the very same thing had happened while we were flying overhead patrolling a mostly irrelevant no-fly zone. This would have been an intolerable humiliation and we inevitably would have ended up bombing on behalf of the rebels. We’re looking at the same choice now. Are we really just going to fly overhead to watch from above as Qaddafi continues to prosecute his dismayingly effective counter-offensive? The debate over the no-fly zone should be understood as merely a proxy for the debate over whether we are going to intervene militarily to topple Qaddafi or not.

Put another way, advocates of a no-fly zone at this point are kidding themselves that their recommendation will accomplish anything, or they are trying to push for a much more significant military intervention without explicitly calling for one. They can engage in outraged denials that they want anything more than a no-fly zone, when they must want a more significant military intervention if they aren’t simply engaged in bellicose posturing. If there is this much political resistance here in the U.S. and in Europe to a no-fly zone, we can easily imagine how much stronger the resistance will be to a more extensive military campaign.