Mr. Obama, who is waiting for a list of options he ordered up (from the Pentagon in particular) last week, said Monday that there continues to be "unacceptable" violence in Libya, and that NATO allies are discussing a wide range of options, including potential military measures. Defense Secretary Robert Gates will join NATO defense ministers Thursday in Brussels to discuss international options in the crisis, including the possibility of imposing a no-fly zone.

But in the meantime, the president has given enough pointers to suggest how any eventual US intervention would be oriented: It would be international in scope – no go-it-alone action – and it is likely to be devised so that Africans and Muslims, and preferably Libyans themselves, were at the vanguard of any steps aimed at Qaddafi.

"If you had to sum up in a few words Obama’s vision of international intervention, it would be 'multilateral if we can, unilateral only if we must, and the military should not be the first option,' " says Lawrence Korb, a senior fellow at the Center for American Progress in Washington and a former assistant secretary of defense in the Reagan administration.

"He's also distinguishing between a vital national interest, and what is nice to have, and it is hard to see how ... we have a vital national interest in Libya," Mr. Korb says.

Obama critics including John Bolton, the former US ambassador to the United Nations under President Bush, fault the president for at best offering some rhetoric on the situation – Obama's statement Thursday, for example, that Qaddafi has lost legitimacy and must relinquish power – and for ceding leadership of the international effort against Qaddafi to the British, French, and even (gasp!) UN Secretary General Ban Ki-moon. [my emphasis]

... the U.S. (and international) interest here is humanitarian, not strategic, which does not by itself mean that we should do nothing. What is going on in Libya does not constitute genocide -- a deliberate attempt to exterminate a whole category of people -- but the government's actions are clearly brutal, inhumane, and almost certainly involve war crimes. It thus falls squarely under the heading of the "Responsibility to Protect" doctrine (R2P), a new norm of humanitarian intervention promulgated with some fanfare a few years ago. R2P says "where a population is suffering serious harm, as a result of internal war, insurgency, repression or state failure, and the state in question is unwilling or unable to halt or avert it, the principle of non-intervention yields to the international responsibility to protect" [Walt's emphasis]

But here's where it gets messy (as usual). Russia opposes outside military intervention in Libya, which means that the Security Council is unable to authorize intervention along the lines suggested by R2P. (This is one reason why some of us were skeptical about the whole R2P initiative from the get-go). An alternative approach would have NATO or the EU or some coalition of regional organizations authorize outside action, but as numerous observers have already noted, this approach generates echoes of past colonial interference and could lend a certain (false) credence to Qaddafi's propaganda, which has sought to portray the rebels as some sort of foreign plot. Then remember that U.S. military forces are badly overstretched (which is why Secretary of Defense Robert Gates has been pouring cold water on the idea of a no-fly zone), and we've spent the past decade fighting wars in several other Muslim countries. Add all this up, and Obama's reluctance to send the Marines or impose a "no-fly zone" is understandable. It is not entirely clear that such a zone would make that much difference. [my emphasis]

Senate Foreign Relations Committee chairman John Kerry, D-Mass., today said setting up a controversial no-fly zone over the country would not cross the line into military intervention.

"The last thing we want to think about is any kind of military intervention. And I don't consider the no-fly zone stepping over that line," Kerry said on CBS' "Face the Nation" Sunday.

"We don't want [U.S.] troops on the ground. [The rebels] don't want [U.S.] troops on the ground. That would be counterproductive," Kerry told CBS News chief Washington correspondent Bob Schieffer. But he said that the U.S. ought to be prepared to set up a no-fly zone (although there would be no grounds to implement it until asked by U.S. allies). ...

Schieffer noted that Secretary of Defense Robert Gates has been skeptical of a no-fly zone, saying it is harder to implement than one might think. "[Gates] says basically that's going to war, because he says if you're going to have a no-fly zone, you've got to go in there and bomb their anti-aircraft installations there, that you're going to be bombing the country," Schieffer said.

"That's actually not the only option for what one could do," Kerry replied. "One could crater the airports and the runways and leave them incapable of using them for a period of time." He said a no-fly zone would not amount to war, or even military intervention. [my emphasis]