No-fly zone or no no-fly zone. That was the big question in Europe today as Britain’s David Cameron and France’s Nicolas Sarkozy pushed in Brussels for limited military action to ground Libya’s Air Force.

Yet a no-fly zone to prevent Muammar Qaddafi's forces from staging air strikes against beleaguered rebels did not take wing among European leaders. Several cited “collateral damage” or civilian deaths as too great a possibility.

As Libya’s uprising reaches its third week and Mr. Qaddafi's position is strengthened, a no-fly zone, or something like it, is a growing dilemma for the West.

Speaking on a BBC panel taped Friday, Oxford scholar Khaled Hroub is dubious about a no-fly zone over Libyan airspace. But talk to Mr. Hroub away from the microphones and he says a no-fly zone may be possible if carried out intelligently.

If Qaddafi starts a bloodbath, a “nuanced” air campaign carefully put together by President Obama in a way that Libyans can clearly see is being done for their benefit, to save lives, might work, he says.

The problem is that, says to Hroub, “Qaddafi is right now sowing confusion on every front in Libya. Confusion is the name of his game. For a no-fly zone, the Libyans need to see this is something they can accept. The format and how it is done is crucial. Maybe with Obama. Two years ago the idea would be rejected."

Rebels are asking for help from the front lines, and Western leaders say they want to back them and the democracy movement.

But the list of legal, technical, and other problematic downsides grows longer every day: how do you help without getting trapped in a war, how do you support an Arab uprising without taking it over, and how does the US and Europe help without seeming to serve their own interests.

Creating a no-fly zone involves actions akin to war. Michael Lind in Salon described the no-fly zone as the camel’s nose under the tent for a larger war.

As British diplomat Sir Jeremy Greenstock put it on the BBC panel conducted at Chatham House, “If we help the opposition [in Libya] we inspire the radicals in the Gulf. If we don’t help, we inspire repressive regimes” that want to block the changes now underway in the Middle East. "The consequences of the consequences could be very severe," he said.

Sir Greenstock added that it is only after “seven to 10 years” that the effects of intervention can be properly weighed.

Practically alone on the BBC panel, Davis Lewin of the London-based Henry Jackson Society argued that opposition figures crying for help on the battle field deserve support, that there is a combination of moral and strategic rationales, that only the US could provide the necessary leadership, and that “every day” that passes the moment for a historic resolution is being squandered. “Obama and Cameron have already said Qaddafi must go. If he stays in power now what message is that sending?”

When or if to offer assistance to Libyan rebels runs through a terrifically difficult set of questions and previous cases.

Some in the audience at Chatham House argued for intervention on humanitarian grounds. Yet with an Iraq war winding down and an Afghan war expected to escalate this spring, if the West decides to take action, so the argument went, Libyans and Arabs need to see the action is done for humanitarian reasons. That would require the West, then, to actually do it for humanitarian reason, and not for more strategic calculations.