Whether it is a matter of weeks or months, Libyan leader Muammar Qaddafi will probably fall from power, and opposition forces will likely gain control of most of Libya.

In Afghanistan, the United States has begun withdrawing troops and allies are following suit. Over the next few years, despite best efforts to train Afghan security forces, Afghanistan's corrupt and ineffective government will likely have to accommodate radical Islamist Pashtuns (the Taliban in all but name) in the south and east, and acknowledge the old Northern Alliance's sway in the north. The west of the country will remain heavily influenced by Iran.

The best-case scenario may simply be that the central government does not collapse when international forces fall below critical mass.

It is a brutal irony: In Libya, NATO made a half-thought-through effort, with the US in the back seat, and may inadvertently succeed. In Afghanistan, with eight years of hard work, massive US leadership, and more than 150,000 troops on the ground, NATO has made little lasting impact and is beginning a retreat without a clear victory. It's a strange and troubling outcome – and a bad one for NATO – on all counts.

Lessons for US and Europe

The lessons Americans and Europeans may take from these episodes are as different as they are telling. Americans will likely blame Europeans for never doing their share in Afghanistan. And whether Libya is a success or failure, it will prove to Americans that the US should no longer offer defense capabilities that Europe itself will not fund.

Europeans, meanwhile, may conclude it was a mistake to follow the US into Afghanistan in the first place, and that the drawn-out operation in Libya further proves that expeditionary missions are a bad idea. Europe should stay close to home and practice genuine self-defense.

The one thing both sides would agree on is that for whatever we face in the future, NATO is not up to it. But in a world in which ideological, military, economic, political, and sheer chaotic threats are growing, shouldn't Europe and North America, these twin pillars of democratic values in the world, act together more closely than ever before?

If so, what are the real conclusions allies should draw from NATO's current operations? Here are some suggestions:

Lesson One: NATO and US must both take ownership

First, for NATO to mean anything, both sides of the Atlantic need to take ownership of the alliance.

At the moment, for both America and Europe, "NATO" has become synonymous with "them." When an American president speaks of "handing over to NATO," he means "Europe" – as though America, long the leader of NATO, is no longer in it. At the same time, for Europe, "NATO" has been long equated with "the Americans." The alliance is hollowing out from within.

Lesson Two: Europe's defense cuts undermine alliance

Second, as underlined by former Secretary of Defense Robert Gates, the demolishing of European defense budgets is hastening this effect. Europe lacks the capabilities to accomplish basic combat missions without the US. This was a problem long before the Libya operation put it in stark relief.

If Europe continues to shed real defense capabilities, there will be no alliance to speak of.

Lesson Three: US can't abandon NATO

Third, the US cannot abdicate NATO leadership. This does not mean acting unilaterally, but neither can the US take a back seat. It is understandable that Americans would be frustrated that Europe does not pull more of the load. But an America that "leads from behind" is not leading at all.

We must lead, and bring others with us. By rejecting this role in Libya, the US is allowing NATO to appear a paper tiger. That serves no one's interests.

Lesson Four: Shore up solidarity

Fourth, we must shore up solidarity within the transatlantic family, which has eroded dramatically in recent years. The EU is fracturing over the euro debt crisis. In Afghanistan, every ally agreed to take part, but several placed "caveats" on their forces. In Libya, the US itself has become a caveat country.

This trend away from real solidarity must be reversed.

Lesson Five: NATO needs vision public will support

Finally, NATO needs a role that publics will genuinely support with resources and political will. At its 2010 Lisbon summit, NATO agreed on an ambitious new strategic concept that says NATO should do just about everything. But instead of implementing this vision, allies are slashing defense budgets, withdrawing troops, cutting costs at NATO headquarters, and ignoring civilian contributions.

Where does this leave NATO as it approaches a 2012 summit in Chicago? Ideally, we would all recommit to the fully resourced and robust NATO that meets the security needs of the 21st century. But if that bar proves too high, perhaps the opposite is in order.

A "back to basics" NATO that focuses on the collective defense of the allies may be the most that publics and finance ministries will sustainably support. Which means that for complex, expeditionary, and combat missions, whether on Europe's periphery or beyond, the old "coalition of the willing" concept is looking better and better.

Kurt Volker, a former US ambassador to NATO, is managing director, international, for BGR Group and senior fellow and managing director of The Center for Transatlantic Relations at Johns Hopkins University's School of Advanced International Studies. A version of this essay originally appeared in Italy's La Stampa newspaper.