Libya stalemate leaves Nato without 'Plan B'
"Stalemate" is not a word you will hear in public from the lips of ministers or media handlers in the Ministry of Defence here in London.
It was the British and the French, of course, who were at the forefront of pushing for military action in Libya.
Earlier this week, following talks with his French counterpart, UK Defence Secretary Liam Fox rejected any idea of a military stalemate, noting that the mission to defend the population in Libya would continue.
"It is very important," said Mr Fox, "that we give no sign of any wavering in our resolution."
Nonetheless there will be sighs of relief in London, Paris and beyond at the initial reports of rebel advances in and around the besieged town of Misrata.
Behind the scenes, though, there is growing concern at the duration of the campaign and the fact that political rhetoric seems to have outstripped what the military means available can deliver.
One of America's leading defence commentators, Prof Tony Cordesman of the Centre for Strategic and International Studies in Washington, puts it this way: "The mission can only succeed if Gaddafi and his regime are made the primary target and driven from power."
Pretending that a no-fly zone or striking at small, dispersed Libyan units can be sufficient "is farce and not the effective use of force," he says.
Another expert, Andrew Bacevich, professor of international relations at Boston University, is even blunter: "Nato has gotten itself into a real pickle", he told me.
"The way out seems pretty clear - taking Col Gaddafi out of the equation will probably take the fight out of Libya's forces," said Prof Bacevich.
"Since Gaddafi probably can't be bought, he's going to have to be killed.
"My guess is that alliance leaders understand that, even if they won't say it out loud."
Nato air power has so far prevented the rebel forces from being defeated but it cannot ensure their victory. Air power has struggled even to lift the siege on the town of Misrata.
But almost from the outset, the goal of the operation has been confused.
The UN resolution authorising the use of force is wide-ranging, but solely devoted to the protection of the civilian population. It's not a justification for regime change.
Nonetheless, several of the key governments involved in the operation - not least the US, the British and the French - have made no secret of their desire to see Col Gaddafi gone.
Veteran US foreign policy analyst Leslie Gelb worries that the goal of getting rid of the Libyan leader has meant that too little attention has been given to diplomatic efforts to end the crisis. The intervention of African Union leaders back in mid-April was one such moment.
"I think they [Nato] missed an opportunity with the African presidents' ceasefire proposal," says Mr Gelb.
"The African leaders proposed a too-narrowly-defined ceasefire. The Nato response should have been to define it more broadly, especially since Col Gaddafi accepted it."
In recent days, there have been more Nato air attacks against command centres in Libya - targets where at least potentially the Libyan leader may be. He has not been seen for a number of days. Many analysts wonder if he is now indeed an explicit target.
However, long-time Nato analyst Prof Sean Kay is worried about just such a post-Gaddafi scenario.
"Gaddafi's departure might actually solve little if the nation breaks down into a Somalia-type civil war," he told me.
"The best we can hope for at this stage is a de facto partition of Libya - certainly not something the Nato allies had aspired to when this adventure began.
"No matter what the outcome," he says, "it is very hard to imagine scenarios where Nato ground forces in some kind of peacekeeping role will not be needed in Libya, and likely for a very long and expensive duration."
But there is no going back now. All we are really left with at this stage are questions: Can Col Gaddafi be forced from power one way or another?
What might a post-Gaddafi Libya look like? How might a diplomatic resolution be negotiated? Is a messy cease-fire, with Col Gaddafi still holding sway in Tripoli, the more likely outcome?
Tony Cordesman has already established some of the lessons that he thinks should be drawn from this crisis.
"Don't begin a military option without a realistic strike plan and the willingness to use decisive force," he says.
The focus, he believes, should be on "the total humanitarian cost of military action, and not simply on limiting the damage done by individual strikes. Consider the cost of days, weeks, and months of additional fighting to the entire population as well."
Thinking back to those days in mid-March when air operations began, few if any of the governments involved probably imagined that Col Gaddafi would still be in power some two months later. The skids, it seemed, were under both him and his regime. He looked like history.
Fast forward to today and that seems wishful thinking.
Was insufficient force used, as Tony Cordesman asserts? Or were diplomatic opportunities along the way squandered, as Leslie Gelb argues?
Either way, things have not turned out quite as the British, French and Americans expected. Having started the air campaign, they seem to have no other approach but to continue with it.