Twenty-five years ago this November, an East German Politburo member bungled the announcement of what were meant to be limited changes to travel regulations, thereby inspiring crowds to storm the border dividing East and West Berlin. The result was the iconic moment marking the point of no return in the end of the Cold War: the fall of the Berlin Wall. In the months that followed, the United States, the Soviet Union, and West Germany engaged in fateful negotiations over the withdrawal of Soviet troops and the reunification of Germany. Although these talks eventually resulted in German reunification on October 3, 1990, they also gave rise to a later, bitter dispute between Russia and the West. What, exactly, had been agreed about the future of NATO? Had the United States formally promised the Soviet Union that the alliance would not expand eastward as part of the deal?
Even more than two decades later, the dispute refuses to go away. Russian diplomats regularly assert that Washington made just such a promise in exchange for the Soviet troop withdrawal from East Germany -- and then betrayed that promise as NATO added 12 eastern European countries in three subsequent rounds of enlargement. Writing in this magazine earlier this year, the Russian foreign policy thinker Alexander Lukin accused successive U.S. presidents of “forgetting the promises made by Western leaders to Mikhail Gorbachev after the unification of Germany -- most notably that they would not expand NATO eastward.” Indeed, Russian President Vladimir Putin’s aggressive actions in Georgia in 2008 and Ukraine in 2014 were fueled in part by his ongoing resentment about what he sees as the West’s broken pact over NATO expansion. But U.S. policymakers and analysts insist that such a promise never existed. In a 2009 Washington Quarterly article, for example, the scholar Mark Kramer assured readers not only that Russian claims were a complete “myth” but also that “the issue never came up during the negotiations on German reunification.”
Now that increasing numbers of formerly