The more important question is what exactly a no-fly zone would achieve. Certainly, it would ground Gadhafi’s air force, but it would not come close to ending the fighting nor erode Gadhafi’s other substantial advantages. His forces appear to be better organized and trained than his opponents, who are politically divided and far less organized. Not long ago, Gadhafi largely was written off, but he has more than held his own — and he has held his own through the employment of ground combat forces. What remains of his air force has been used for limited harassment, so the imposition of a no-fly zone would not change the military situation on the ground. Even with a no-fly zone, Gadhafi would still be difficult for the rebels to defeat, and Gadhafi might still defeat the rebels.

The attractiveness of the no-fly zone in Iraq was that it provided the political illusion that steps were being taken, without creating substantial risks, or for that matter, actually doing substantial damage to Saddam Hussein’s control over Iraq. The no-fly zone remained in place for about 12 years without forcing change in Saddam’s policies, let alone regime change. The same is likely to be true in Libya. The no-fly zone is a low-risk action with little ability to change the military reality that creates an impression of decisive action. It does, as we argue, have a substantial downside, in that it entails costs and risks — including a high likelihood of at least some civilian casualties — without clear benefit or meaningful impact. The magnitude of the potential civilian toll is unknown, but its likelihood, oddly, is not in the hands of those imposing the no-fly zone, but in the hands of Gadhafi. Add to this human error and other failures inherent in war, and the outcome becomes unclear.