This BBC News note is useful in reflecting thusly

1417: "I think the no-fly zone is a red herring. It's essentially shorthand for, 'Do something, but make sure it's sanitized so there are no messy consequences.' The problem is that it won't be sanitized," writes Judah Grunstein in the World Politics Review Trend Lines blog. He calls instead for a "a rapid and brief series of air strikes to destroy Libya's air force" on the ground.

As is this U.S. Ambassador to NATO: No-fly zone wouldn’t help much - By Josh Rogin | The Cable

"[I]t's important to understand that no-fly zones...really have a limited effect against the helicopters or the kind of ground operations that we've seen, which is why a no-fly zone, even if it were to be established, isn't really going to impact what is happening there today," Daalder said. "And the kinds of capabilities that are being used to attack the rebel forces and, indeed, the population will be largely unaffected by a no-fly zone. "

However, there is another question to consider: if nothing is done, what happens?

From what I am seeing and hearing via my sources in the Maghreb, there is a significant chance of an enduring civil war and even if Qadhdhafi regained control, one would not see a return to the pre-war situation, but probably the emergence of in fact an Al Qaeda linked type of running insurgency. This in particular as the West would been seen as having thrown the rebellion to the Guide's Dogs, there is very likely to be a natural turn to the clandestine Islamist radicals - who are the most likely to survive the "ratissage" après rebellion.

As Obama et al are no longer facing the choice of "unfortunate stability with a dictator" or "allowing political transition"(à la Egypt, Tunisia), but various forms of horror and civil war that are likely to be profoundly destabilizing - not just re Libya and its oil fields(*) but also re Tunisia and Egypt, the policy analysis needs to sit up and take notice. Iternvention and support to rebellion are not good choices at all, not as easy as internet whanking makes it out to be, but on the other hand, the flip side looks possibly even uglier. It may not be a question of a winning hand, but a less-losing hand.

This note from Michael Hudson, "As the U.S. considers intervention in Libya, it should look to history" is useful.

As for the American invasion of Iraq, the folly of that endeavor -- in logic, planning, and execution -- has deeply eroded American credibility throughout the region; and the authoritarian regime (despite its "elected" character) that replaced Saddam Hussein is now eliciting the same kind of mass protests that we are seeing in North Africa, Jordan, and even the Gulf. The chief beneficiary has been Iran, while Washington has little to show for eight years of material and human expenditure

....

A truly "rogue regime" until it discovered the virtues of making up with the West, Qadhafi's bizarre family-tribal military autocracy is counter-attacking against the determined, enthusiastic, but poorly organized and ill-equipped protest movement. The convergence of morality and interests is understandably generating pressure for the U.S. to come to the rescue militarily.

But before using force in the present case, the U.S. needs to look back at its own decidedly mixed record in the region and consider the following five simple rules for intervention:

1) Don't come in unless invited. As the well-armed British SAS agents discovered, the Libyan rebels don't welcome foreign soldiers. Still less will they welcome American boots on the ground, considering the interventionist baggage the U.S. carries. Qadhafi, on the other hand, could make political hay out of overt U.S. involvement.

2) If you feel you must go in, don't go in alone. Join with the neighbors who are closest to the conflict. In the Libya case this means Arab neighbors first of all -- Egypt, Tunisia and Saudi Arabia. Secondarily, western allies might help, but remember the bad memories Libyans have of Italian and British colonialism.

3) Be prepared for things that will go wrong. As our previous interventions have shown, Murphy's Law invariably applies. Sometimes there is a happy ending as in Lebanon in 1958. But most of the time the intervener gets stuck in the mustanq'a -- the swamp of local conditions that we only superficially understand. Which is why Rule 4 is important.

4) Don't overstay your welcome. One of the rallying cries of the nationalists (led by Qadhafi) in 1969 was the closure of Wheelus Air Force base -- then the largest base outside the U.S. Even if desperate rebels might initially accept an ongoing U.S. presence, the Libyan public will resist anything that looks like the re-establishment of a Western military presence. A post-Qadhafi regime foolish enough to encourage such a permanent engagement would soon be confronting its own rebels, including incidentally radical Islamists.

5) Consider the alternatives. Look before you leap. This is not the time for the Marines to march toward the shores of Tripoli again. Troops on the ground, even if invited by the rebels, will create more problems than they solve. A no-fly zone, according to Secretary of Defense Gates, cannot be established without destroying Qadhafi's air defenses first. The Libyan protesters need weaponry to confront Qadhafi's tanks and armor on the ground. It is hard to imagine that Saudi Arabia and the U.S. are not already working to provide it. It is politically acceptable for the rebels discreetly to receive Western arms and intelligence support, but Americans should never be firing the guns.

Emphasis added. These are very good observations. And returns to my earlier obs re getting some NATO ally with access to Sov style equipment compatible with what the Libyan rebels largely already heave. Ukraine might be good sourcing point (corruptly if nothing else) but Polish trainers are more politically reliable. "Surplus" Sov era anti tank and AA man portables would do some good, but only with trained units / groups. Helping the defecting military commanders slap together a bit of military discipline would be helpful - but outsiders can't make that happen, except in the limited sense of throwing in behind the rebels in a way that they can feel - useful that it's France with no direct history in Libya - to help avert reverse defections.

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(*: yes oil matters, it matters for Western economies and as much it matters for developing economies which are going to suffer even more than the USA or the West from a massive oil shock, and one driven by nothing untoward that either the West or they have done [as no one bears responsibility for Qadhdhafi but himself])

__ ETA
In my original posting I hadn't read this Fareed Zakaria note, but it is well-worth a read The Libyan Conundrum - TIME

So the U.S. must follow through in its efforts to get Gaddafi out of office, pushing all diplomatic levers and seeking maximum multilateral support. It should ask the Libyan opposition for a public set of requests, so that Washington is seen as responding to Libyans, not imposing its will. If the Libyans request military assistance, Washington should move in that direction. I don't believe that a no-fly zone is a magic bullet. It is a high-profile policy that puts the U.S. military directly into the conflict but would actually make little difference. Gaddafi's main advantage is not in the air but on the ground. He has tanks, armored vehicles and massive firepower. The basic military question is hence how to shift the balance of power away from him and toward the rebels.

Over the past five decades, the U.S. has had very mixed results when it has intervened, by air or land, in other people's wars. But it has done pretty well when it has helped one side of the struggle. Arming rebels in Afghanistan, Central America and Africa has proved to be a relatively low-cost policy with high rates of success. Giving arms, food, logistical help, intelligence and other such tools to the Libyan opposition would boost its strength and give it staying power.

"

And also thinking along the same lines as myself:

Some worry that if we arm the rebels, things might turn out the way they did in Afghanistan, where the freedom fighters became Islamic jihadists and turned their sights on us. But that's not really what happened. After the Soviet defeat, the U.S. abandoned Afghanistan, leaving it open to Islamic jihadists backed by the Pakistani military. The better analogy is to Chechnya, where as the civil war continued, the rebels became more radical and Islamic fundamentalists jumped into the fight and soon became its leaders. The best way to prevent al-Qaeda from turning Libya into an area of strength would be to have the fighting end — with Gaddafi's defeat. So let's help the Libyan opposition do it.