For those interested:
http://www.juancole.com/2011/03/an-open-letter-to-the-left-on-libya.html
In his survey of possible left positions, Juan seems to leave out one key dimension: results. His position seems built on the assumption that the rebels will quickly overthrow Gaddafy. If they do that in less than 90 days, and the no-fly zone is not renewed, it would indeed seem hard to make a retrospective case against it.
But there is another possibility, which people have built opposing left positions on, namely that the rebels never overthrow Gaddafy, and the no-fly zone thus becomes a permanent aerial occupation (since any lifting of it would allow the slaughter that it is now postponing) and de facto partition of the country for decades (as happened in the wake of the original no-fly set up in Northern Iraq in 1991).
I'm sure Juan can give more reasons for why he thinks the odds are high that Gaddafy will get quickly overthrown with no more help than this. I'll pass them on if he posts them in the future.
Michael