Is the United Nations making a comeback? The UN Security Council resolution authorizing the use of force in Libya suggests that it is less than irrelevant. President Obama, reluctant to intervene, was pushed, or shamed, into acting, partly by the Arab League's approval of a no-fly zone, followed by the UN.

To hear Obama's critics tell it, the Libyan imbroglio is the equivalent of Abyssinia in 1935-36--a clear case of the failure of western nerve. The Italians used poison gas to try and subdue the Ethiopians. Now Qaddafi is bombarding his own population.

The question Obama will face is how far he should go in Libya. He can likely stop Qaddafi from taking Benghazi, a city that few Americans had even heard of until a week or so ago, but that has now become the Sarajevo of 2011. It's fascinating how these international conflicts become the cockpit of domestic disputes. The neoconservative Foreign Policy Initiative, for example, released a letter the other day addressed to Obama that implored him to establish a no-fly zone. The names on the letter were pretty much the sames ones that signed the Project for the New American Century's missive calling for ousting Saddam Hussein.

The most likely outcome is a standstill in Libya, a form of partition. But maybe the UN can be brought in as a broker. What would be the safe haven that it could arrange for Qaddafi? Saudi Arabia has become a destination point for pensioner dictators, but the dislike is mutual between Qaddafi and the House of Saud. So that's no go. Perhaps Qaddafi could simply traipse around the world since he does seem to have a nomadic soul.

The truth is that Qaddafi may well hunker down in Libya. The country will become increasingly immiserated as oil flows only slowly. So Obama has a choice. He can interven and maintain the status quo. Or he can go for the knockout blow, a risky move that could have enormous political benefits at home.

If Obama goes down as the great liberator of Libya, it will solidify his foreign policy bona fides immensely. Until now, he has played the realist. Now Qaddafi's slaughter of his brethren is forcing Obama as well as the UN to adopt a new role.