However, now the policy has fallen apart and presented the alliance with its greatest crisis in a quarter-century.
For NATO's forces in Afghanistan are no longer peacekeepers. They are being forced to defend themselves as warriors. And they lack the numbers, the air power and the logistical support to even defend themselves adequately.
NATO's peacekeeping role in Afghanistan was supposed to mark a proud milestone for the venerable alliance. Instead of defending the democratic nations of Western Europe from communist aggression as it did so successfully for 40 years through the Cold War, the new, broader and grander NATO was supposed to step out on to the world stage and "export security" to unstable nations that needed it throughout the Middle East and Central Asia.
Afghanistan, unlike Iraq, was supposed to be an ideal pioneering showcase for this new role. There was not supposed to be a war to fight as the United States and its Afghan allies had already topped the Taliban in the winter of 2001-2002. And Afghanistan was not a controversial war among America's European NATO allies the way Iraq became from the very beginning.
The need to topple the Taliban who had protected Osama bin Laden and al-Qaida while they plotted the Sept. 11, 2001, atrocities was obvious to all. German Chancellor Gerhard Schroeder, who later suffered President George W. Bush's enmity for opposing the war in Iraq, took huge political risks earlier when he took the unprecedented decision to deploy thousands of German soldiers in Afghanistan outside the territory of NATO's member states for the very first time in the history of Germany's participation in the alliance.
President Bush and U.S. Defense Secretary Donald Rumsfeld welcomed the idea of handing over security responsibilities in Afghanistan to their NATO allies and to Australian forces because it could obscure from the American public the embarrassing fact that the United States was becoming totally isolated in Iraq in real terms.
Even Britain, the one effective U.S. military ally in Iraq, is preparing to pull its ground forces out of that country. Also, precisely because Bush and Rumsfeld thought the Afghan war was already won, they did not mind handing over peacekeeping in Afghanistan to a NATO alliance and to European allies that they have consistently treated with contempt over the past six years.
But the whole U.S. and NATO strategy in Afghanistan rested on two false assumptions: The first was that the war was over and that the Taliban and their allies could never seriously revive there. However, they have indeed done so. And now they have already Afghan President Hamid Karzai of effective power anywhere where U.S., NATO and Australian soldiers do not patrol outside his capital Kabul.
The second false assumption of U.S. policymakers was even more serious. It was that NATO -- which has been steadily expanding in member states and total population since the collapse of communism, could project any real military power outside the borders of its constituent nations.
Instead, NATO's fate since the collapse of communism has been that of a rapidly expanding ink blot: The further it grows, the feebler it becomes.
Far from growing in military power, NATO has been steadily losing it, precisely because none of its new members is capable of exporting military and security beyond their own borders. Germany and France have only feeble independent airlift capabilities beyond NATO's European heartland. Britain, supposedly the most impressive European NATO member in terms of such capabilities, is down to only five aging Lockheed Martin Tristars, that can carry a total of 1,330 troops and their automatic rifles and personal gear at any one time.
So feeble is Britain's independent airlift capacity that, as recent articles in the British press have documented, the 8,000 exhausted and overstretched British troops still serving across southern Iraq have had to endure vastly extended tours of duty there because Royal Air Force lacks the airlift capacity to rotate them out and replace them.
And in Afghanistan, British units under attack from Taliban and other rebel guerrilla forces have had to wait for up to four hours for that support to come because the available air support capability is so limited.
The U.S. Air Force alone of the major NATO allies retains a truly formidable tactical ground support force. A single supersonic B-1 bomber can now deliver a rain of devastating ordinance with unerring accuracy on to any pinpointed target anywhere in Afghanistan -- or anywhere else, for that matter.
But the U.S. Air Force, like the other U.S. armed forces, already has its hands full in Iraq. Therefore any additional military conflict, or the immediate threat of one, with either North Korea or Iran -- let alone countries at the same time -- would stretch its operational capabilities to the limit.
NATO was not supposed to need to rely on U.S. air power in Afghanistan. The conflict there was supposed to be over, not escalating, and the Atlantic Alliance was supposed to be getting stronger, not weaker.
Instead, the ever expanding balloon full of hot air that NATO has become is being humiliated by the same relative handful of Afghan tribal warriors who were supposed to have been lastingly routed four and a half years ago.
As Stanley Kober of the Cato Institute in Washington told UPI, "The fate of NATO is being decided on the hills of Waziristan."
It is not a reassuring prospect.