Politicians on both sides of the Atlantic are fond of describing NATO as the most successful military alliance in modern history. Who can blame them? The transatlantic partnership between Europe and America brought peace to a war-torn continent, overcame the Soviet challenge, and provided a safe haven in which to nurture European political and economic integration. Security ties between Europe and America also facilitated cooperation on a host of other issues, and helped foster a remarkable period of material prosperity.
Given these achievements, it is hardly surprising that few voices now call for an end to the alliance, and equally unsurprising that pundits like Zbigniew Brzezinski believe it can work a similar magic in areas far beyond NATO's original mandate. Unfortunately, such claims ignore the deep structural forces that are already beginning to pull Europe and America apart. Instead of becoming the core of an expanding security community, united by liberal values, free markets, and strong international institutions, the transatlantic partnership that fought and won the Cold War is already showing unmistakable signs of strain. No matter how many new states join NATO, and no matter how many solemn reaffirmations emerge from the endless parade of NATO summits, the high-water mark of transatlantic security cooperation is past.
The reasons are not difficult to discern. For the past forty years, the partnership between Europe and the United States was held together by three unifying forces. The first and most important was the Soviet threat. The second was America's economic stake in Europe, which reinforced its strategic interest in European prosperity. The third was the existence of a generation of European and American elites whose personal backgrounds and life experiences left them strongly committed to the idea of an Atlantic community.
