Meeting at the alliance headquarters in Brussels just hours after planes struck the World Trade Center on Sept. 11, 2001, Nick Burns, then U.S. ambassador to the North Atlantic Treaty Organization, thought he would have to do some convincing to get the rest of the NATO member countries to come to America's defense. But rather than show any hesitation, he says, America's allies immediately volunteered their support, even before the casualty counts had become clear. "It was a great moment of alliance solidarity on a very tragic day," Burns, who's now an international relations professor at Harvard's Kennedy School of Government, recalls.
All at once, the original purpose of NATO was both revived and demonstrated to be outdated. Indeed, in the immediate term, the attacks on America gave the values-based alliance a renewed relevance in a post-Cold War world. But over the intervening decade, the issues surrounding the global struggle against terrorism have also added new layers of complexity and raised new questions about the alliance's future.
On Sept. 12, 2001, as an act of solidarity with Americans after the previous day's catastrophe, the allies invoked Article 5—the binding promise of the group's mutual defense—for the first time in history. Originally designed with Russia in mind, Article 5 says that for all member states, "an armed attack against one or more of them in Europe or North America shall be considered an attack against them all." The countries stood by the United States with a sense of urgency and energy. "The expectation was for 50 years that it would be the United States that would have to rush to the defense of Europe in the event of a war against the Soviet Union, and the irony was that the only time we had ever invoked Article 5 was that next day, and it was for the Europeans to rush to defend the United States," Burns says.
As the realities set in, it soon became clear that the gesture had opened NATO up to an entirely different set of challenges than most had previously considered. For one, the enemy was not a country, but a group of non-state actors, al Qaeda. Also, the threat of terror gave NATO countries, whose united cause had been based on the notion of protecting a geographic location, a new function. They could no longer just defend their own territory; to fight against terrorists, they'd have to go far beyond. "This was NATO's natural progression after 9/11," says Burns. "It became very clear to us that while Europe was largely peaceful and secure, the interests of the NATO members were being directly affected by terrorism [and] what became the wars in Afghanistan and Iraq. So, it became very clear that NATO had to go well outside of its natural geographic area because the interests of our members were being threatened."
The threat of terrorism was at that moment, more than ever, seen as a global issue that couldn't be fought successfully by one country alone. Cooperation, whether through NATO, the United Nations, or more ad hoc partnerships, was essential. "We live in this age when all of the really interesting security challenges are too big for one state to deal with alone," says Jeff Lewis, director of the East Asia Nonproliferation Program at the Center for Nonproliferation Studies at the Monterrey Institute of International Studies. "So, you have to have cooperation, and alliances are a major point of cooperation."
Even just a month after the World Trade Center and Pentagon attacks, news reports reflected hopeful sentiments that the tragedy could be a chance for rejuvenation for NATO, the decline of which had been a common global talking point through the previous decade. But as the United States began its campaign against terrorists in Afghanistan in October 2001, Americans led by President George W. Bush initially seemed to rebuff NATO's efforts and take things into their own hands, says Stewart Patrick, director of the International Institutions and Global Governance Program at the Council on Foreign Relations. That changed in 2003, he says, after the United States also decided to invade Iraq. "It was only later that, and partly because the U.S. was feeling spread pretty thin after the invasion of Iraq, that the United States really became open to the notion of NATO taking over ISAF, or the International Security Assistance Force, in Afghanistan," Patrick says.