Enlargement of NATO

Based on Wikipedia: Enlargement of NATO

The Promise That May or May Not Have Been Made

In 1990, during negotiations over German reunification, American Secretary of State James Baker sat across from Soviet leader Mikhail Gorbachev and floated an idea. What if, Baker suggested, NATO's jurisdiction didn't extend "one inch to the east" beyond a reunified Germany?

Whether that suggestion constituted a promise—and if so, what exactly was promised—remains one of the most consequential disputes in modern geopolitics. It's a dispute that Vladimir Putin would later cite to justify invading Ukraine. It's also a dispute that shapes how we understand why a military alliance formed in 1949 now stretches from the Atlantic Ocean to the borders of Russia itself.

The North Atlantic Treaty Organization, better known as NATO, started with twelve countries agreeing to defend each other against Soviet aggression. Today it has thirty-two members. How that happened—and what was said, implied, or understood along the way—is a story of collapsed empires, broken expectations, and the messy business of redrawing the map of Europe.

Twelve Nations Against the Soviet Threat

NATO's founding members in 1949 were an eclectic group: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States. What united them wasn't geography—Portugal and Iceland share little in common—but fear of Soviet expansion.

The arrangement was straightforward. An attack on one member would be considered an attack on all. This principle, enshrined in Article 5 of the North Atlantic Treaty, meant that any Soviet military move into Western Europe would trigger American involvement. For war-weary European nations still rebuilding from World War Two, this American security guarantee was invaluable.

Greece and Turkey joined in 1952, driven by the Cold War's logic. Greece had just emerged from a brutal civil war against communist forces. Turkey's newly elected Democrat Party was staunchly pro-American. Both faced pressure—internal and external—to align firmly with the West.

Then came the question of Germany.

The Problem of a Divided Germany

After World War Two, Germany was split into two countries. West Germany, officially the Federal Republic of Germany, was aligned with the Western democracies. East Germany, the German Democratic Republic, was a Soviet satellite state. The United States, France, and Britain occupied West Germany and controlled its foreign policy.

The occupying powers wanted to end their occupation, but they had a problem. A non-aligned West Germany that could rearm independently made everyone nervous. The solution? Make West Germany's NATO membership a condition for ending the occupation.

The Soviets proposed an alternative: a neutral but unified Germany. The Western allies dismissed this as insincere—a ploy to weaken the alliance. France delayed the process, demanding a referendum in the Saar region first. Finally, in May 1955, West Germany joined NATO.

The Soviet response was immediate. Within weeks, they established their own collective defense alliance: the Warsaw Pact. Europe was now formally divided into two armed camps.

Spain's Long Road In

Not everyone who wanted to join NATO could simply walk through the door. Spain under dictator Francisco Franco presents an interesting case.

Franco was fiercely anti-communist—exactly the kind of leader you might expect NATO to embrace during the Cold War. But Franco had cooperated with Nazi Germany and Fascist Italy during World War Two. NATO members remembered this. In 1955, Franco reportedly feared that any Spanish application would be vetoed.

Instead, Spain worked around NATO. Franco signed bilateral defense agreements with individual members, including the 1953 Pact of Madrid with the United States, which gave Americans access to Spanish air and naval bases. It was NATO membership in everything but name.

After Franco died in 1975, Spain began its transition to democracy. International pressure mounted for Spain to normalize relations with Western democracies. But even then, joining NATO was politically fraught. Prime Minister Adolfo Suárez moved carefully, wary of divisions in his coalition over American bases on Spanish soil.

The catalyst came from an unexpected direction. In February 1981, members of Spain's Civil Guard stormed the Congress of Deputies in an attempted coup. The coup failed, but it exposed how fragile Spain's young democracy was. The new Prime Minister, Leopoldo Calvo-Sotelo, championed NATO membership partly to strengthen civilian control over the military. Spain joined in May 1982, and a 1986 referendum confirmed public support.

France's Complicated Relationship

Being a NATO member doesn't mean you have to like NATO. France proved this dramatically in 1966 when President Charles de Gaulle withdrew French forces from NATO's integrated military command structure and ordered all foreign NATO forces out of France.

De Gaulle wasn't leaving the alliance entirely—France remained committed to collective defense in principle. But he bristled at American dominance and wanted an independent French foreign policy. NATO headquarters relocated from Paris to Brussels. France wouldn't fully rejoin the integrated command structure until 2009.

Greece had its own complicated moment. In 1974, Turkey invaded Cyprus following a Greek-backed coup attempt on the island. Greece suspended its NATO membership in protest. The irony was acute: two NATO allies in military conflict over a third country. Greece rejoined in 1980, with Turkish cooperation, but the Cyprus issue remains unresolved today.

The Wall Falls, and Everything Changes

By the mid-1980s, the Warsaw Pact was crumbling from within. The Soviet Union, struggling with economic stagnation and nationalist movements in its republics, could no longer hold its alliance together by force.

Poland held multiparty elections in June 1989. The communist Polish Workers' Party was voted out of power. Then, in November 1989, East Germans began dismantling the Berlin Wall. People who had lived their entire lives unable to visit the other side of their own city suddenly streamed through in both directions.

The Cold War was over. Now what?

Reunifying Germany Without Losing NATO

The negotiations to reunify Germany consumed most of 1990. The central question: what happens to NATO?

East Germany had been Warsaw Pact territory. If it merged with West Germany, would the unified country be in NATO, the Warsaw Pact, or neither? The Western powers insisted on NATO. The Soviets, understandably, had reservations about NATO forces stationed on what had been their side of the line.

The compromise, embodied in the Two Plus Four Treaty signed in September 1990, prohibited foreign troops and nuclear weapons from being stationed in the former East Germany. But an addendum—signed by all parties—specified that foreign NATO troops could be deployed east of the Cold War line after Soviet forces departed, at the discretion of the unified German government.

This is where things get murky.

The treaty itself says nothing about other countries joining NATO. It deals only with Germany. But during the negotiations, various statements were made—by Baker, by German Foreign Minister Hans-Dietrich Genscher, by others—that have been interpreted very differently by different parties ever since.

Gorbachev later said that NATO enlargement "was not discussed at all" in 1990. But he also described NATO's expansion beyond East Germany as "a violation of the spirit of the statements and assurances made to us in 1990."

This distinction—between the letter and the spirit of what was agreed—would haunt European security for decades.

The Soviet Union Dissolves

The Warsaw Pact formally dissolved in July 1991. A few months later, the Soviet Union itself ceased to exist.

The process was remarkably swift. Republics in the Baltic region—Estonia, Latvia, Lithuania—declared independence. Ukraine followed in August 1991. By December, the Soviet flag was lowered over the Kremlin for the last time.

Russia, led by President Boris Yeltsin, emerged as the largest and most powerful of the successor states. But it was a diminished power, struggling with economic collapse and political chaos. The countries that had once formed its buffer zone against the West now faced a choice: which direction would they turn?

The Visegrád Group Charts Its Course

In February 1991, Poland, Hungary, and Czechoslovakia formed the Visegrád Group. Named after a town where medieval kings of these countries once met, the group had a clear purpose: push for integration with Western Europe through the European Union and NATO.

NATO's initial reaction was lukewarm. At the 1991 Rome summit, members agreed to a series of goals that could eventually lead to accession—market reforms, democratic liberalization—but stopped short of extending invitations.

Inside the American government, debate raged. Some officials saw NATO enlargement as a wise move to strengthen Western influence in a region where the Soviet collapse had created a power vacuum. Others worried about provoking Russia or overextending the alliance.

The debate intensified during Bill Clinton's presidency. Should NATO offer full membership quickly to a few select countries? Or should it pursue a slower approach, gradually bringing in a wider range of states?

The 1994 congressional elections, which brought Republican majorities to both houses of Congress, tilted the balance. Republicans advocated aggressive expansion. Clinton made NATO enlargement a centerpiece of his foreign policy. In 1996, he publicly called for former Warsaw Pact countries and post-Soviet republics to join the alliance.

Russia's Shifting Position

Russian reactions to NATO enlargement were complicated and evolved over time.

In August 1993, Polish President Lech Wałęsa was campaigning for Poland's NATO membership. Yeltsin reportedly told him Russia didn't view Polish membership as a threat. But Yeltsin reversed himself the following month, writing that enlargement "would violate the spirit of the treaty on the final settlement" and "precludes the option of expanding the NATO zone into the East."

By 1996, Russian Foreign Minister Andrei Kozyrev openly opposed enlargement. Yet in May 1997, Yeltsin signed the NATO-Russia Founding Act, which stated that "NATO and Russia do not consider each other as adversaries" and acknowledged that "NATO has expanded and will continue to expand."

Yeltsin called NATO enlargement a mistake but argued the Founding Act would minimize the damage. Russia's December 1997 National Security Blueprint, however, described eastward NATO expansion as "unacceptable" and a threat to Russian security.

This pattern—grudging acceptance mixed with warnings about red lines—would define Russian policy for years.

The First Wave: Poland, Hungary, Czech Republic

At the 1997 Madrid summit, NATO invited Poland, Hungary, and the Czech Republic to join. Slovakia, the other Visegrád member after Czechoslovakia's peaceful dissolution, was excluded. NATO members cited undemocratic actions by Prime Minister Vladimír Mečiar as the reason.

Not everyone in the West supported this expansion. More than forty American foreign policy experts—including former senators, defense secretaries, and security advisors—signed an open letter to Clinton expressing concern. They argued enlargement was expensive and unnecessary given the lack of a Russian threat at that time.

Hungary held a referendum on membership in November 1997. The result: 85.3 percent in favor.

In March 1999, Poland, Hungary, and the Czech Republic officially joined NATO. The alliance had crossed into former Warsaw Pact territory.

The Big Bang: Seven More Members

At the 1999 Washington summit, NATO introduced "Membership Action Plans"—standardized roadmaps for countries aspiring to join. Albania, Bulgaria, Estonia, Latvia, Lithuania, North Macedonia, Romania, Slovakia, and Slovenia all received individualized plans.

In 2000, nine of these countries formed the Vilnius Group to coordinate their membership campaigns. At the 2002 Prague summit, seven received invitations: Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia.

The Baltic states—Estonia, Latvia, Lithuania—were particularly significant. These weren't just former Warsaw Pact members. They had been part of the Soviet Union itself, forcibly incorporated in 1940. Their accession brought NATO to Russia's border.

Slovenia held a referendum in 2003. Sixty-six percent approved membership. All seven countries formally joined at the 2004 Istanbul summit.

The Adriatic Two and Beyond

Albania and Croatia joined on April 1, 2009, just before the Strasbourg-Kehl summit. Montenegro followed in June 2017. North Macedonia—after resolving a long-running name dispute with Greece that had blocked its accession—joined in March 2020.

Each accession followed the same basic pattern: aspiring members reformed their militaries, aligned their political systems with NATO standards, and navigated the domestic politics of joining a military alliance. Some faced referendums. All faced scrutiny from existing members.

Russia Invades, and the North Expands

In February 2022, Russia invaded Ukraine. President Vladimir Putin cited NATO's eastern expansion as justification, arguing that NATO military infrastructure in Ukraine and the country's potential membership posed a threat to Russian security.

The invasion had the opposite effect Putin intended.

Finland and Sweden, both historically neutral, applied for NATO membership in May 2022. Finland, which shares an 830-mile border with Russia, had maintained a policy of military non-alignment since World War Two specifically to avoid provoking its neighbor. Sweden hadn't fought a war since 1814. Both countries concluded that Russian aggression made neutrality untenable.

Finland joined in April 2023. Sweden followed in March 2024. NATO's border with Russia roughly doubled in length.

Ukraine's Application and the Question of Future Expansion

Ukraine applied for NATO membership in September 2022, after Russia illegally annexed portions of the country's southeast. The application came amid active warfare—an unprecedented situation for an alliance that has never admitted a country engaged in armed conflict.

Other countries have also expressed interest. Bosnia-Herzegovina and Georgia have informed NATO of their membership aspirations. Kosovo, which declared independence from Serbia in 2008 and isn't universally recognized, also aspires to join.

The question of NATO membership remains actively debated in several European countries: Armenia, Austria, Cyprus, Ireland, Malta, Moldova, and Serbia all face domestic discussions about their security alignments.

The Disputed Promise Revisited

Did Western leaders promise Gorbachev that NATO wouldn't expand eastward? The question has never been definitively resolved.

Historians have examined the documentary record extensively. Political scientist Marc Trachtenberg concluded that allegations by Russian leadership about informal assurances "were by no means baseless." There's evidence that Soviet negotiators believed they were receiving such assurances, even if nothing was formally committed to paper.

Putin has promoted this narrative aggressively, including in a notable 2007 speech in Munich. He used it to justify Russia's actions in Ukraine in 2014 and the full-scale invasion in 2022.

Western governments counter that no binding commitments were made, that the discussions concerned only Germany, and that sovereign nations have the right to choose their own alliances. They note that the NATO-Russia Founding Act, which Russia signed, explicitly acknowledged NATO's continued expansion.

Both sides have documents and statements to cite. Both sides interpret the same evidence differently. What's clear is that the period around 1990-1991 created expectations—on all sides—that were never fully aligned, and that this misalignment has had catastrophic consequences.

What NATO Membership Requires

Joining NATO isn't simply a matter of expressing interest. Article 10 of the North Atlantic Treaty specifies that only "European States" may be invited. This is why the United States and Canada, founding members, represent the only non-European countries in the alliance, and why Australia or Japan couldn't join even if they wanted to.

Aspiring members must complete a multi-step process. They engage in political dialogue with existing members. They undertake military reforms to ensure their forces can operate alongside NATO militaries. They demonstrate commitment to democratic governance, market economies, and the peaceful resolution of disputes.

The North Atlantic Council—NATO's governing body, where each member has one vote—ultimately decides who receives an invitation. Decisions are made by consensus, meaning any single member can block a candidate. Turkey, for instance, delayed Sweden's accession over disputes about Kurdish organizations operating from Swedish territory.

The Alliance Today

From twelve founding members in 1949, NATO has grown to thirty-two. It has expanded ten times, absorbing countries from every corner of Europe. Its eastern frontier now runs along the borders of Russia, Belarus, and Ukraine.

The alliance that formed to contain Soviet expansion has outlived the Soviet Union by more than three decades. It has proven more durable and more attractive than its founders could have imagined. Countries line up to join. None have left, though France temporarily withdrew from military integration and Greece briefly suspended participation.

Whether this expansion enhanced European security or contributed to the very conflicts it was meant to prevent depends on whom you ask. What's certain is that the decisions made in the years after 1989—about who would be invited, when, and with what assurances to Russia—continue to shape the world we live in.

The promise that may or may not have been made still echoes.