The crisis in Libya is shaping up to be what those in the industry call a mass atrocity event. Marc Lynch captures the mood among several commentators who are rightly calling for some sort of intervention to halt the ongoing atrocities.

We should not be fooled by Libya’s geographic proximity to Egypt and Tunisia, or guided by the debates over how the United States could best help a peaceful protest movement achieve democratic change. The appropriate comparison is Bosnia or Kosovo, or even Rwanda where a massacre is unfolding on live television and the world is challenged to act. It is time for the United States, NATO, the United Nations and the Arab League to act forcefully to try to prevent the already bloody situation from degenerating into something much worse.

By acting, I mean a response sufficiently forceful and direct to deter or prevent the Libyan regime from using its military resources to butcher its opponents. I have already seen reports that NATO has sternly warned Libya against further violence against its people. Making that credible could mean the declaration and enforcement of a no-fly zone over Libya, presumably by NATO, to prevent the use of military aircraft against the protestors. It could also mean a clear declaration that members of the regime and military will be held individually responsible for any future deaths. The U.S. should call for an urgent, immediate Security Council meeting and push for a strong resolution condeming Libya’s use of violence and authorizing targeted sanctions against the regime. Such steps could stand a chance of reversing the course of a rapidly deteriorating situation. An effective international response could not only save many Libyan lives, it might also send a powerful warning to other Arab leaders who might contemplate following suit against their own protest movements.

There has been a sort-of coalescing around the idea that a No Fly Zone is useful way to intervene to stop the killing. I am not so sure. While it is true that some of the slaughter has been perpetrated by Libyan air force, air assets alone are not responsible for the killing. If Qaddafi and his inner circle are intent on violently suppressing this revolt, they will use their superior ground forces as well.

A No Fly Zone is a humanitarian half measure. It would let the international community say that it is doing something, but there is very little a No Fly Zone can actually do to stop ongoing slaughter. Using Lynch’s comparisons to slaughters of the 1990s, people need to ask themselves: would a no-fly zone have stopped the Machete wielding Interhamwe from perpetrating the Rwandan genocide? Definitely not. In Bosnia, there was an effective NATO enforced no fly zone over in 1995 when Srebrenica occurred. During the 1999 Kosovo air campaign, as NATO was bombing Serbia, Serb forces accelerated their ethnic cleansing in Kosovo. No Fly Zone’s may be good at enforcing a stalemate like interwar Iraq, but it is lousy at preventing slaughter.

This is not to say there is no utility in trying to enforce one over Libya—as Marc Lynch says, it could be one of several demonstrations of the resolve of the international community (along with multilateral sanctions and, perhaps, a Security Council referral to the ICC.) But we should not delude ourselves into thinking that a no-fly zone is an effective humanitarian response to a mass slaughter event. It is a gesture. Not a response.

If stopping a slaughter is our top priority, then a more robust response is probably required. That means not just preventing airplanes and attack helicopters from flying over Libya, but defeating the Libyan military infrastructure that is perpetrating the violence. The word for that is war.

While a U.S/NATO backed military intervention might be effective at halting the ongoing violence, it may also undermine some of the longer-term goals of a nascent democracy movement in Libya. After all, the United States/NATO would be intervening on behalf of one side of a civil war (that’s true, even if the level of intervention is only to enforce a No Fly Zone). Given the level of mistrust of the United States, such overt support for the anti-Qaddafi side may backfire — not to mention the fact that people generally don’t like to be bombed by foreigners.

This is the big policy dilemma facing the international community—and especially the United States. Intervene forcefully to stop the slaughter and risk undermining the long-term prospects for democracy, or “stand by” and watch the Libyan military massacre hundreds or even thousands of people.

That’s probably why half measures like a No Fly Zone seem so attractive right now. But we are deluding ourselves if we think that this alone will stop the slaughter or serve the long term interests of Libyan democrats.