Rather than teeing up the rebels for a military vicotry that now seems increasingly unlikely, it's a safe bet that any no-fly zone would be tied to efforts to broker a political solution.
No-fly zone is one way to ensure a stalemate in Libya
As recently as a week ago, a no-fly zone over Libya was still spoken of as a means of dramatically accelerating Col Muammar Qaddafi's ouster, and minimising its human cost. It was assumed that depriving Col Qaddafi of the advantage of air power would enable rebel forces - perhaps with a shipment of antitank weapons - to sweep into Tripoli and send the tyrant packing.
But even as the Arab League on Saturday provided crucial diplomatic cover for a no-fly zone, it's purpose now may be more about stopping the war than about finishing it. To borrow a metaphor from motor racing, a no-fly zone may have become more akin to the yellow flag produced after an accident that obliges contestants to slow down and keep to their current positions.
Arab League leaders emphasised the no-fly zone as a means of protecting civilians and ending violence, in order to save Libya from the consequences of further fighting. "What is happening now to the Libyan people poses a threat to the security and stability of Arab states," said Oman's foreign minister, Yusuf bin Alawi. "If the Arab League does not take responsibility to prevent a downward spiral, that could lead to internal fighting or unwanted foreign intervention."
Rather than teeing up the rebels for a military victory that now seems increasingly unlikely - given the military imbalance between the two sides - it's a safe bet that any no-fly zone would be tied to efforts to broker a political solution.
Col Qaddafi's forces have used their overwhelming advantages in armaments and organisation to recapture Zawiya to the west of the capital and threaten Misurata, the last rebel-held town on that side of the country. They have also driven the rebels back along the coastline, out of Bin Jawad and Ras Lanuf, and threaten to overrun Brega and drive on to Ajdabiya, in a push to reverse the rebellion's westward march from Benghazi.
The rebellion, in fact, appeared in real danger of defeat by the weekend, an object lesson in the dangers of going to war without a proper army and a clear political and military strategy.
Nobody is expecting a rebel assault on Tripoli any time soon, although the regime may not be in a position to retake the rebel "capital" of Benghazi, either. They've dislodged the rebels from positions taken on trucks and riding to distant towns, but as the insurgents find themselves retreating onto home ground with the wall at their backs, Col Qaddafi may not have the manpower to crush the rebellion at its source.
So, even if a no-fly zone were implemented immediately, it would be likely to enforce a kind of de facto partition along the lines of the civil war frontier. The goal of regional and global powers is likely to ensure that the civil war is not protracted by pressing for a political solution that involves regime change - even if mustering the necessary leverage to achieve that goal could take many months of arming, training and professionalising rebel forces, and imposing the economic and diplomatic isolation that renders the regime's survival untenable in the long run.
Col Qaddafi has the upper hand militarily, but he has no political or diplomatic road out of the crisis. The Arab League and the EU have recognised the legitimacy of the rebellion, and humanitarian and economic aid is expected to begin pouring into rebel-held territory.
The popular protest against the Col Qaddafi regime evolved within days into an armed rebellion, whose chances of success were then dependent on the ability of its heroic citizen-fighters to beat the better armed, trained and organised forces of the regime, and on the ability of its leadership in Benghazi to muster support.
In both respects, Libya's unrest has been very different from the people power revolutions of Tunisia and Egypt, which relied on the energies and courage of unarmed citizens in numbers that prompted the army to remain on the sidelines, leaving both regimes untenable.
Of course, everything from Libya's social structure to the composition of its armed forces and the willingness of its regime to unleash brutal violence against dissenters combined to produce a different path there. But that path has run into some of its limitations.
As the respected retired diplomats of the International Crisis Group wrote last week: "Qaddafi built a power structure centred around him and family members and dependent in part on tribal alliances rather than modern structures. As a result, the army and security forces could not remain neutral [as happened in Egypt]; they have split between forces loyal to one side or the other. The country also appears to be dividing along tribal and regional lines."
Col Qaddafi, for his part, has been shrewd in his use of air power, slowing momentum for a no-fly zone by directing his air attacks at specific rebel targets but apparently avoiding mass casualty bombing raids against civilian targets. This has left many Western leaders arguing that the Libyan regime has yet to cross a line that would "trigger" international intervention.
Col Qaddafi is hemmed in by a raft of sanctions and diplomatic isolation that could make his regime untenable in the long run. But right now, he appears unlikely to be forced out by a rebel assault on the capital. A no-fly zone, if one were to be enforced now, would serve more to protect the rebellion's eastern core than enable it to storm Col Qaddafi's citadel. And the international focus will then likely turn towards seeking some form of cease-fire, and protracted negotiations, over reuniting the country under a new political order.
Col Qaddafi won't go easily, of course, and the rebel leadership will have to hone a strategy that involves a combination of economic, diplomatic, political and, probably, military pressures over many months. The dramatic events of the past month in Libya may simply have been the opening act.
Tony Karon is an analyst based in New York. Follow him on Twitter @TonyKaron