In the post-Cold War era, the United States is partly to blame for the world view that it is the ultimate guarantor of stability. In today's multipolar world, that is a role that it cannot afford.
Timely warning that Nato risks becoming a relic
To call a colleague irrelevant would seem a strange way to motivate. But perhaps the outgoing American defence secretary, Robert Gates, saw no other option: Nato needed a wake-up call.
The world's most powerful military alliance faces "the very real possibility of collective military irrelevance", Mr Gates told European allies at the weekend. The United States, he said, cannot foot the bill for Europe's security forever.
These are not new criticisms, but today they carry added weight. As Nato stumbles along in Afghanistan, and grinds to a halt in Libya, the alliance is being tested in a changing world.
There is the basic question whether the "North Atlantic Treaty Organisation" has strayed too far from its original purpose of containing the Soviet Union's Warsaw Pact. Two decades after the Cold War, the victors are still caught in anachronistic habits.
While the 28 member states in North America and Europe share a broad interest in stability, it's pure fiction that they all have the same priorities in each and every eventuality. In Afghanistan, allied force contributions remain a fraction of the US commitment - while the invasion was led by America, the mutual defence pact obliged Nato members to commitments that most have since failed to honour.
Nato's inconsistencies in Libya are even more pronounced. While the air campaign is international in name, the military responsibilities are being carried out by a handful of nations, namely France and Britain supported by non-Nato members like the UAE and Qatar, who simply cannot match the US capability to project force.
In the post-Cold War era, the United States is partly to blame for the world view that it is the ultimate guarantor of stability. In a multipolar world, that is a role that it cannot afford. Allies not only in Europe but in Asia as well have to assume more of the expense of their own defence, although that often faces budget complaints and sceptical publics.
Despite the challenges it would be too early to write the alliance's obituary. For all its failings, Nato continues to engage in valuable missions, from counter-piracy efforts off the Horn of Africa to terrorism patrols in the Mediterranean Sea. And yet, as Mr Gates said, Nato's longevity is no longer guaranteed. Nor should it be.
As the world is seeing in Libya, military might alone will not solve the crises. Alternative solutions - such as the Libyan Contact Group, which met in Abu Dhabi last week - are needed. The time of an over-arching "evil empire" is past; alliances now need to deal with the more nuanced complexities at a local and regional level. Nato may play a role, but it is far more than the North Atlantic at stake these days.