Advocates of NATO enlargement speak in nebulous terms about fostering cooperation and promoting stability throughout Europe. Indeed, many of them downplay NATO’s military significance, portraying the alliance as primarily a political association in the post‐​Cold War era.

But NATO is first and foremost a military compact to protect its members from armed attack. If NATO moves eastward, the United States will be undertaking new and potentially far‐​reaching security obligations. No amount of “feel good” rhetoric should be allowed to obscure that reality.

There are numerous dangers associated with NATO enlargement. The alliance could become entangled in parochial disputes among the new members, just as it now must constantly fret about the possibility of war between Greece and Turkey. (Hungary, which is certain to receive an invitation to join NATO, has ethnic problems with three neighboring states–Slovakia, Serbia, and Romania.)

Even worse, expanding the alliance to Russia’s borders threatens to poison Moscow’s relations with the West and lead to dangerous confrontations. Extending security commitments to nations in Russia’s geopolitical “back yard” virtually invites a challenge. The United States would then face the choice of failing to honor treaty obligations or risking war with a nuclear‐​armed great power.

Advocates of enlargement should realize that the Central and East European countries do not merely want the status symbol of NATO membership. They believe that membership will give them a reliable security guarantee, since article 5 of the North Atlantic Treaty declares that an attack on one member is an attack on all and obligates every signatory to render assistance.

That desire on the part of Russia’s former Warsaw Pact allies creates difficult enough problems for NATO. On the part of several former Soviet republics (especially the Baltic states), it is even more troublesome, since satisfying those countries would require a highly provocative alliance presence in Russia’s “near abroad.”

Clinton administration officials and other supporters of NATO expansion profess to be baffled at Moscow’s hostile reaction. But even the most peaceably inclined Russian leader would find it difficult to tolerate a U.S.-dominated military alliance perched on his country’s western frontier.

The post‐​Cold War changes that have taken place in NATO’s military orientation heighten Russian apprehension. Throughout the Cold War, Western leaders could credibly argue that the alliance existed solely to defend the territory of member‐​states from attack. But as NATO has ventured into “out of area” missions, most notably in Bosnia, and such prominent supporters of the alliance as former secretary of state James Baker advocate NATO intervention “anywhere and under any circumstances” peace and stability in Europe are threatened, the alliance now clearly has offensive as well as defensive objectives.

Given Russia’s weakened condition, the United States and its allies may be able to force Moscow to accept NATO enlargement accompanied by such sops as statements that the alliance has no plans to station nuclear weapons or large numbers of conventional forces in the new members–plans that can easily be changed at a later date. But someday Russia will recover politically, economically, and militarily. And Russians will likely remember that the West exploited their country’s temporary weakness to establish hegemony throughout Central and Eastern Europe. NATO enlargement, therefore, could become the 1990s’ equivalent of the Treaty of Versailles, which sowed the seeds of revenge and an enormously destructive war.

Moreover, even now Moscow can take several disagreeable actions short of a direct military confrontation. For example, the Russian Duma can reject the Start II nuclear arms reduction agreement. Moscow can also seek closer strategic relationships with China and other powers outside Europe. Indeed, there are already ominous signs of a Moscow‐​Beijing axis. Russian and Chinese leaders speak of a “strategic partnership” between the two countries, and China is now Russia’s largest arms customer.

As NATO expands eastward, Russia can create its own political‐​military bloc among those nations that are not included on the roster of new NATO members. The agreement between Russia and Belarus suggests a willingness to construct such a bloc. Russia’s ability to move westward as NATO moves eastward creates a particularly thorny dilemma for the alliance. If enlargement comes in stages, with only a few Central European countries offered membership initially, Moscow has a clear incentive to preempt further rounds by consolidating its own sphere of influence. Yet a single, comprehensive expansion that incorporates not only the Central European countries but Moscow’s other erstwhile Warsaw Pact allies and the Baltic republics would be so provocative as to guarantee a second cold war–or worse.

An enlarged NATO is a dreadful, potentially catastrophic idea. Instead of healing the wounds of the Cold War, it threatens to create a new division of Europe and a set of dangerous security obligations for the United States.