French President Nicolas Sarkozy and British Prime Minister David Cameron at the Elysee palace

From James Blitz, the Financial Times:  “Libya came out all right in the end,” says Kurt Volker, a former US ambassador to Nato. “But if we come to a quick judgment that this mission was a Nato success story, and don’t have a serious discussion of its strengths and weaknesses, we will never get to the bottom of some of the problems plaguing the alliance. . . .”

From a military perspective, there was also one core success: the accurate use of air power to destroy Col Gaddafi’s ground assets. In this conflict, Nato showed the increasing efficacy of air-launched weapons. “We demonstrated that we can use these missiles in very congested urban centres without incurring collateral damage,” says a senior Nato air chief.

However, the mission also reaffirmed the dictum that air power alone does not guarantee total victory. Nato jets undertook nearly 8,000 strike sorties against regime targets but Nato planners realised the Gaddafi government would not crumble until rebels emerged as a capable fighting force. “Without a ground component, things tend to stagnate, which is what we saw for the first few months while the Libyan forces got their act together,” says Col Peter Mansoor, a former executive officer to US General David Petraeus in Iraq.

In Britain, senior Ministry of Defence figures say one of the biggest military lessons arises from the transformation of the rebels into credible fighters. According to one such official, not all of this was thanks to Nato nations: “The countries that deserve most credit in this conflict are Qatar and the United Arab Emirates. They provided the rebels with the training and weapons they needed, and acted as their leaders.”

This is instructive for Britain and other Nato states, says the official. “We don’t want to repeat the mistake that’s often made of regarding the war that’s just ended as the template for all future ones. But we need to think harder about our capacity to train proxy fighters on the ground at speed. After the wars in Iraq and Afghanistan, western states will be reluctant to commit their own troops to a ground campaign for years to come. There needs to be more focus in Nato nations on the need to have training teams at high readiness that can turn a proxy army into an effective fighting force. . . .”

[M]any believe the declining defence capability of the Europeans – which is being savaged by budget cuts – bodes ill. Britain would still be able to carry out a medium-sized operation of the kind seen in Libya one year from now. But it would deploy considerably fewer aircraft because some of the Tornado jets deployed over Libya will be retired early under defence cuts. The operation also proved the limitations of European capabilities in any Nato operation not involving the US. Without America’s technical backbone – Tomahawk cruise missiles, drones and electronic warfare aircraft to guide combat missions – the Libya mission could not have succeeded.

“We’ve learnt that Nato is unprepared for even relatively simple operations without appreciable American logistical support,” says John Nagl of the Center for a New American Security, a Washington-based think-tank. “We’ve seen the costs of long-term underinvestment by European nations.”

When the Friends of Libya (as the country’s international backers call themselves) meet in Paris on Thursday, such concerns will be put to one side. All thoughts will be on the fall of Col Gaddafi – and what the new authorities in Tripoli need to entrench stability. There will be a celebration, too, of new military relationships that have been boosted by this mission – most notably between Britain and France, and between Nato and the Gulf Arab states.

However, the Libya conflict of 2011 has also cast a shadow over the transatlantic defence relationship. In time, the war will come to be remembered by historians as the moment when one of the most notorious despots of the Middle East was toppled by international action. But it may also come to be seen as the point when the US signalled to the nations of Europe that they must start thinking harder about how to provide security in their own backyard.

As Professor [Michael] Clarke of Rusi puts it: “Nato should think long and hard about this operation. Whatever it represents to the Libyan people, it may come to look like a tipping point in the transatlantic evolution of Nato.”