Joshua R. Itzkowitz Shifrinson — Put It in Writing — How the West Broke Its Promise to Moscow

During negotiations over German reunification in 1990, did the United States promise the Soviet Union that NATO would not expand into eastern Europe? The answer remains subject to heated debate. Today, Moscow defends its invasion of Ukraine by claiming that NATO reneged on a promise to stay out of Russia’s backyard. Skeptics, meanwhile, counter that Russian claims are a pretext for aggression; in their view, Washington and its allies never formally committed to forego NATO expansion. 

The skeptics are correct that the two sides never codified a deal on NATO’s future presence in the east. But they misinterpret the precise implications of negotiations that took place throughout 1990. After all, scholars and practitioners have long recognized that informal commitments count in world politics. This was particularly true during the Cold War: as the historian Marc Trachtenberg has shown, the Cold War settlement itself emerged from European, Soviet, and U.S. diplomatic initiatives in the late 1950s and 1960s that were not formalized until nearly a decade later. 

However problematic its recent behavior, then, Moscow has reason to argue that the West broke a promise. As declassified U.S. documents show, the George H. W. Bush administration and its allies worked hard to convince Soviet leaders that Europe’s post–Cold War order would be mutually acceptable, as the Soviet Union would retrench and NATO would remain in place. Yet U.S. policymakers may not have intended to make this vision a reality. And although there are many reasons to criticize recent Russian behavior, Russia may not be lying when it claims that a promise was broken. In the end, the United States overturned the system it promised to bring about.…

Foreign Affairs — a publication of the Council on Foreign Relations
Put It in Writing — How the West Broke Its Promise to Moscow
Joshua R. Itzkowitz Shifrinson

Also,  Mary Elise Sarotte, A Broken Promise? — What the West Really Told Moscow About NATO Expansion

Now that increasing numbers of formerly secret documents from 1989 and 1990 have made their way into the public domain, historians can shed new light on this controversy. The evidence demonstrates that contrary to the conventional wisdom in Washington, the issue of NATO’s future in not only East Germany but also eastern Europe arose soon after the Berlin Wall opened, as early as February 1990. U.S. officials, working closely with West German leaders, hinted to Moscow during negotiations that month that the alliance might not expand, not even to the eastern half of a soon-to-be-reunited Germany. 

Documents also show that the United States, with the help of West Germany, soon pressured Gorbachev into allowing Germany to reunify, without making any kind of written promise about the alliance’s future plans. Put simply, there was never a formal deal, as Russia alleges -- but U.S. and West German officials briefly implied that such a deal might be on the table, and in return they received a “green light” to commence the process of German reunification. The dispute over this sequence of events has distorted relations between Washington and Moscow ever since.