PERSPECTIVE ON NATO : Back to Square 1 With Einstein : U.S.- Europe links still look like the Cold War, not the global alliance we would seek if starting from scratch.

In one of his most famous gedanken (thought) experiments, Einstein asked what would happen to a set of twins if one of them traveled through space at a speed near that of light while the other remained on Earth. He showed that the space traveler would return to Earth far younger than his twin. In this way, Einstein demonstrated an important insight that helps form the basis of modern physics.

If physicists can pose seemingly nonsensical questions to learn something important, why not analysts of policy? Imagine, for example, two worlds: In one, the Cold War world, NATO exists. The other is a world just like today’s, except NATO does not exist. This gedanken experiment’s question: Would the United States try to re-create it?

During the Cold War, American security concerns focused on Europe because our security interests there were strong. Moreover, they were directly threatened by the Soviet Army, which confronted Allied forces across the East-West dividing line. A military confrontation in Europe could have easily escalated to a nuclear war involving U.S. territory. NATO was the chief institutional instrument of U.S. security policy. Often the very best of America’s military officers, officials and politicians sought to hitch their careers to the NATO star.

What about the gedanken experiment’s world? Today, America’s security concerns are more diffuse. We worry about threats to our territory from potential new nuclear states or terrorist groups, as well as from the large quantity of weapons and nuclear material in the former Soviet Union. As in the Cold War, we continue to have strong interests in three regions of the world--Europe, Northeast Asia and the Persian Gulf. But political instability is the chief threat to these interests now, not the Red Army.

In Asia and Europe, our interests are geopolitical and economic. We do not want hostile powers to dominate the opposite sides of the oceans that guard our shores. Northeast Asia and Europe are the homes of our strongest trading partners: The strength of our economy depends on theirs. All of us, moreover, depend critically on Persian Gulf oil.

Even as our security concerns in Asia and Europe have become more economic in nature, they have become broader geographically. In Asia, we are seeing the potential development of strong trading partners to the south, such as India and Indonesia. In Europe, the collapse of communism has opened prospects for a geographically broader European Union, as witnessed by the recent addition of Austria, Sweden and Finland and the planned addition of Poland, the Czech Republic, Slovakia and Hungary. Within Europe, our security concerns are largely focused on Germany: If that country is secure, it can lead Europe politically and economically, but will not seek to dominate it.

Facing up to all these challenges will be a tall order. Our security interests are liable to be threatened by political instabilities in the three key geographic zones and by the proliferation of nuclear capabilities across the globe. We will need help to deal with these situations. Neither our current alliances in Asia nor the United Nations will be sufficient. In the gedanken experiment, as in the Cold War, we end up turning to the Europeans for assistance and seek to negotiate a security arrangement with them.

The U.S. agenda in the negotiations would be driven by the new security concerns. First, the United States would be looking for security partners on a global scale, with special focus on the Gulf and the problems of proliferation. In Europe, the United States would be focused on the political instability that could develop in the regions to Germany’s east and to Europe’s south.

The point is that the United States would have no interest whatsoever in negotiating a replica of the NATO treaty, on focusing solely or even primarily on protecting the territorial integrity of the 15 current members of the alliance. The United States would want military partners for global contingencies and would want to plan to protect a broader Europe, either through a deal with the broadening European Union or through a treaty with individual nations.

Our gedanken experiment teaches that the current security arrangements between the United States and Europe are unnatural from the U.S. standpoint and need major changes. The NATO of today looks a lot like the NATO of the Cold War, not like the global security alliance that the United States would seek if starting from scratch. To be sure, NATO has made some changes, but these are minor compared to the requirements sketched here.

There is much resistance to change among bureaucrats and politicians on both sides of the Atlantic. Even the expansion of NATO to Eastern Europe is triggering controversy. An official who proposed making the Persian Gulf an explicit security concern of NATO’s would probably be treated as though he’d lost his mind.

Yet, without sweeping changes in its mission and reach, NATO will wither. It will no longer be at the center of U.S. defense planning; it may not even be seriously considered at the margins. Over time, national payments to joint NATO programs, such as air defense and infrastructure, will slip. And the best officers and officials will look for another career path.

This would be a shame. The habits of cooperation and collective planning in NATO are a tremendous security asset to the United States. They should not be lost. In an hour of need, it might prove as hard to rebuild a withered NATO as to build a spaceship that can travel near the speed of light.