Twenty years ago today, the first major post–Cold War expansion of NATO took place in an unlikely locale: Independence, Missouri. The Czech Republic, Hungary, and Poland officially entered NATO in a ceremony at the Truman Library organized by the U.S. Secretary of State, Madeleine Albright, herself a refugee from Czechoslovakia. She had arranged for the accession ceremony to take place at the Missouri site to honor the president on whose watch the alliance had formed fifty years earlier. The foreign ministers of the new member-states got a ride to Missouri on the secretary’s plane and, while in flight, the Polish foreign minister, Bronislaw Geremek, expressed his gratitude to Albright. He told her that NATO enlargement was “the most important event that has happened to Poland since the onset of Christianity.”

Today historians hotly contest the matter of when, exactly, the idea arose to include central and eastern Europe in NATO. The timing is of more than academic interest, because Moscow’s grievance about when the West decided to make allies out of the countries in the region remains a hot-button issue in U.S.-Russian relations to this day. Some scholars have dismissed the notion that the issue arose soon after the fall of the Berlin Wall at the end of 1989, saying it only came up much later, in the nineties. But evidence now available—including documents that I have gotten declassified from the George H. W. Bush Library and, most recently, the Clinton Presidential Library—shows that speculation about the role of the alliance in central Europe began early in the year 1990 among top policymakers. The evidence also shows that in the early to mid-nineties, the Czechs, the Hungarians, and above all the Poles campaigned vocally for accession, particularly after the Clinton team came into office.

Given that the debate over NATO expansion often focuses on U.S.-Russian relations, it’s worth pausing over the importance of these countries’ own actions and wishes over the full course of the decade between 1989 and their accession. Central and eastern European states wanted to become members of the Western community and its institutions—rather than exist in a gray zone between the West and Russia—and to guard against a resurgent Russia. Eventually they succeeded. But first, they had to overcome Western hesitations.

In fact, one of the earliest documented mentions of post–Cold War NATO expansion to central and eastern Europe was a German comment that it should not happen. In February 1990, the West German foreign minister, Hans-Dietrich Genscher, told his British counterpart that Moscow would presumably want, in exchange for allowing Germany to unify, assurances that the Atlantic alliance not move eastward, because “the Soviet Union needs the security of knowing that Hungary … will not become part of the Western alliance.” Genscher yearned to unify his home country—not least because his home town was behind the Iron Curtain, in East Germany—and was trying to preempt all possible objections.

Central and eastern European states wanted to become members of the Western community and its institutions and to guard against a resurgent Russia. But they had to overcome Western hesitations first.

But central and eastern European governments had priorities of their own. Later the same month, the Hungarian foreign minister, Gyula Horn, publicly speculated about Hungary joining NATO. And at a meeting of Warsaw Pact foreign ministers in March 1990, when the Soviet foreign minister indicated his opposition to NATO’s moving eastward across Germany, he found himself completely alone, with no support from his central and eastern European colleagues. Reading the handwriting on the wall, the Soviet ambassador to West Germany determined that it was unsafe to rely on the Warsaw Pact, given how frail it was. In his opinion, Bonn could clearly, without straining, get “the help of Hungary, Poland, and Czechoslovakia” in order “to bring about the collapse of the Warsaw Pact in the shortest possible time.”

As a result of such speculation, by March 1990 an early assessment had reached the desk of the U.S. Secretary of State, James Baker. In it, the secretary’s staff advised caution. While central European states were understandably looking for guidance at a tumultuous time, the interest of the United States might not lie in taking on “the burden of ‘organizing’ this region,” it read, because “we alone do not have the means but … NATO and the EC surely do.”

Put bluntly, the U.S. priority at the time was not helping central Europe; it was achieving German unification as swiftly as possible, in conjunction with German chancellor Helmut Kohl. But questions about the broader future of European security kept coming up. As Bush prepared for the May 1990 summit meeting with Soviet leader Mikhail Gorbachev, Kohl advised him that Gorbachev “has big problems. His East European allies say they want to be in NATO.” Gorbachev’s adviser Anatoly Chernyaev had recently pointed out the obvious to his boss: “a possible entry by Poland into NATO would push the borders of the Western bloc up to the Soviet border.” Using the theory that the best defense is a good offense, Gorbachev had personally pressed the issue with Baker in May 1990, raising the astonishing thought that perhaps the Soviet Union might join NATO. As Gorbachev summarized his conversation with Baker to the French president, François Mitterrand, a few days afterward, he had told Baker that “we are aware of your favorable attitude toward the several representatives of east European states who have made their intention of leaving the Warsaw Pact known, in order to enter NATO later. But what would be the reaction of the U.S.A. if the USSR expressed a similar wish?”

The U.S. priority at the time was not helping central Europe; it was achieving German unification as swiftly as possible.

Once the U.S.-Soviet summit meeting started, on May 31, 1990, it became clear that the fulcrum of the meeting was, indeed, the issue of whether NATO could move eastward beyond the 1989 line. Arguing that it should be able to do so, Bush skillfully cited the so-called Helsinki principle—the idea that countries had a right to choose their own security alliances, as stated in the Helsinki Final Act, which Moscow had signed. Gorbachev conceded the point, to the great consternation of his own delegation members, who were unable to counter Bush’s argument in any meaningful way.

At that moment Bush and Gorbachev were negotiating over Germany, but Gorbachev’s endorsement of the Helsinki principle had implications for central and eastern Europe as well, since they had also signed on to the same accord. A delegation from the think tank RAND, visiting Warsaw shortly after the summit, was surprised when a Polish general asked how his country could get U.S. forces stationed on Polish territory. The question led to an extended debate over the costs and benefits of potential Polish membership in NATO, with the RAND delegation staying “up late with our new Polish friends drinking vodka and trying to explain … how the U.S. might help secure central Europe’s newly won freedom.”

The combination of Bush’s success at the Washington summit and Kohl’s financial generosity toward Moscow later that summer ultimately secured the necessary Soviet approval for German unification in October 1990—without the concessions over NATO that Genscher had feared might be necessary. In fact, the final settlement on Germany, which Moscow signed in September 1990, explicitly allowed NATO to begin moving eastward over the 1989 line. But by then, Saddam Hussein’s invasion of Kuwait had reoriented U.S. priorities away from Europe. The Gulf War and the collapse of the Soviet Union dominated U.S. foreign-policy making in 1991 and early 1992, and the U.S. presidential election then took priority for the remainder of 1992. The Bush team’s time was up when Bill Clinton won.

With Clinton in office, central and eastern European leaders took every opportunity to bring the question of their region’s future in NATO to the new administration’s attention. In April 1993, for example, the United States invited leaders from the region to the opening of the U.S. Holocaust Memorial Museum in Washington. Leaders such as Czech President Vaclav Havel and Polish leader Lech Walesa met with Clinton behind the scenes. Havel urged the U.S. president to save them from “living in a vacuum. That is why we want to join NATO. In addition, in our values and spirit, we are part of Western Europe.” As a result, Havel was focused “on entering NATO and the EC [European Community] because we see ourselves as Europeans who embrace European values.” Walesa was blunter in his own talk with Clinton: “We are all afraid of Russia … If Russia again adopts an aggressive foreign policy, that aggression will be directed toward Ukraine and Poland.”

Over the course of the next year, Walesa’s language grew increasingly insistent with every conversation he had with the Americans. He lamented that NATO had missed an easy opportunity to expand to the east, namely, “during the collapse of the Soviet Union in 1991.” Now, in the Clinton era, it was “already too late to stop Russia’s full control over the Commonwealth of Independent States,” and Walesa worried that Moscow “won’t stop at the old Soviet frontier.” When his American interlocutors expressed concern about upsetting Russia, Walesa was unfazed: “Let the Russian generals get upset … They won’t launch a nuclear war.”

At one point, Walesa tried to take matters into his own hands. He succeeded in getting Yeltsin to join him for an August 1993 dinner in Warsaw, where the alcohol reportedly flowed unusually freely. Walesa got Yeltsin to issue a statement indicating that Russia would not oppose Polish membership in NATO. Walesa immediately alerted Washington to the opportunity, but to his intense disappointment, Washington still hesitated, and Yeltsin’s aides soon found ways to walk the agreement back. At the start of 1994, Walesa and other Poles complained to their American counterparts that if “no obvious fruits materialized … then they might have to look for ‘other arrangements.’”

Although Walesa did not get the instant NATO membership that he hoped for after his dinner with Yeltsin, his arguments and those of his central European peers had nonetheless planted seeds that would later bear fruit. Members of the RAND group who had visited Warsaw in 1990, for example, would go on to write a series of influential papers and articles calling for NATO expansion throughout the early 1990s. The Republican Party voiced support for enlargement in its 1994 midterm campaigns. And, most important, the appeals from leaders in central and eastern Europe made a deep impression on the U.S. president. Ever the consummate domestic politician, Clinton signaled his support for NATO expansion by giving a major speech in a heavily Polish suburb of Detroit in late 1996.

The U.S. president had come to the conclusion that right was on the side of the countries that had suffered behind the Iron Curtain. Once both Yeltsin and Clinton were safely elected to second terms and reinstalled in office, Washington worked together with NATO leaders to ensure that, in 1997, the alliance would invite Poland, Hungary, and the Czech Republic to begin the necessary political and military preparations for accession two years later, during the alliance’s fiftieth-anniversary year.

Today we speak of NATO expansion almost exclusively in the context of tensions between the United States and Russia. But that history should not obscure the one that belongs to central and eastern Europeans, whose own actions in the decade after the fall of Wall in 1989 had much to do with their countries’ accession to the alliance in 1999. Their calls to be let into NATO—exploratory in 1990, but increasingly insistent throughout the nineties—were ultimately persuasive and played no small role in the start of NATO expansion twenty years ago today.