At the same time, both the United States and Russia’s major Western European partners searched for a mechanism whereby Russia could be reassured by giving Moscow a substantive role in Western security matters without somehow involving an actual veto over decisions that would be seen by the new NATO members as compromising their security. Two attempts—the creation of the Permanent Joint Council in 1997 and its replacement, the NATO-Russia Council (established 2002)—both foundered on the irreconcilability of a “voice but no veto” for Moscow, which meant that Russia’s concerns and objections to NATO policy would never carry the day.

All of these solutions could only work if Russia was sufficiently weak not to register major objections, remained dependent on Western goodwill for economic aid and assistance, and lacked adequate power projection capabilities. But Russia’s economic recovery during the 2000s generated an extensive military reform and rearmament program. This, coupled with a sharp shift in the Putin administration’s thinking about the likelihood of a substantive security partnership with Europe and the United States, increasingly made Moscow much less willing to accept a Western agenda for continued NATO enlargement, while giving the Kremlin greater abilities to raise costs and risks—thus striking at one of the essential compromises that had permitted the first rounds of NATO expansion to move forward. As Russia began to draw its “red lines” against further expansion, European and Eurasian states, worried about being left on the wrong side of any new dividing lines, rushed to secure commitments for their own membership in NATO. Legacy NATO members such as France or Germany continued to support the admission of those new members who filled in “blank spots” in the Balkans (such as Croatia or Montenegro), but began to balk at plans to proffer membership action plans for former Soviet republics. Russia moved to adopt a strategy of more overt political interference and even stirring up conflict in places like Georgia (in 2008) or Ukraine (in 2014) both to make their possible candidacies less attractive but also to expose the hollowness of Western promises to future aspirants. In addition, Russia is probing the strength and depth of NATO commitments, which has had the unexpected consequence of strengthening alliance solidarity but also exposing the fragility of alliance cohesion.

THE UNITED States has always complained that European allies should be spending more on defense. During the Cold War, these jeremiads were kept in check by the reality and immanence of the Soviet threat. After the Soviet collapse in 1991, most NATO countries slashed defense spending.

Collapsing defense budgets in Western Europe thus produced a perverse situation in which expanding NATO simultaneously expanded the American share of NATO’s spending—in contrast to the implicit promises to American taxpayers that enlarging the alliance would expand the number of bill-payers for European security. While some newer members of the alliance may have been prepared to spend a higher portion of their gdp on defense, the smaller size of their economies did not, in absolute terms, reduce the size of the U.S. contribution. Today, the United States covers some 70 percent of NATO’s costs even though the economies of the EU members in NATO collectively is larger than America’s.

Even as new members of NATO pleaded for entry into the alliance, citing the perceived threat from Russia, most did not spend as if that threat was imminent. Even as late as 2016, two years after the Russian incursion in Ukraine and after the 2014 Wales summit whereby all NATO members committed to increase spending, only Poland and Estonia, of the post-Cold War new members, were meeting the 2 percent of gdp commitment. (Of the legacy members, only the United States, Britain and Greece were in compliance that year.) Moreover, alarmist calls that NATO, without the United States—despite having a population of more than 500 million people, a combined gdp exceeding $10 trillion and two nuclear powers—would be unable to withstand a head-to-head confrontation with a Russia that had only a fraction of its economy and population seemed to highlight less a Russian threat than a European hope for the United States to keep shouldering that defense burden.

U.S. officials have long recognized that this was not a sustainable bargain. The Washington Treaty’s rarely-cited Article III states that NATO members “separately and jointly, by means of continuous and effective self-help and mutual aid, will maintain and develop their individual and collective capacity to resist armed attack.” It is telling that seventy years ago the Treaty’s drafters—among whom the United States was unquestionably dominant—chose to emphasize this commitment to adequate military spending by placing it before the well-known Article V commitment to mutual defense. They did so knowing that after the destruction inflicted by World War II, Washington would bear considerable responsibility for any “mutual aid.” Yet even then, America insisted that “self-help” must be obligatory.

Robert Gates, who served as secretary of defense in both the Bush and Obama administrations, was neither the first nor the last senior U.S. official to warn NATO allies that relative spending and capabilities were not sustainable. In 2011, when World Bank statistics showed the EU economy to be about 20 percent larger than that of the United States, Gates presciently stated that “future U.S. political leaders … may not consider the return on America’s investment in NATO worth the cost.” Though he could not have predicted Donald Trump, Gates wisely saw that the European failure to address long-standing U.S. concerns could not but provoke a response.

The way America’s Atlantic lobby had presented its case for NATO expansion only exacerbated this problem. For example, during rather limited Senate debates on the later rounds of NATO enlargement, advocates never brought up the possible costs and risks of confronting Russia and instead insisted that expanding the alliance would bolster American efforts in the war on terror and in military missions in the Greater Middle East. While it is true that Central European states and other aspirant countries like Georgia provided forces to U.S. wars in Iraq and Afghanistan, they did so in a transparently transactional manner, hoping to secure American support and protection against an increasingly problematic Russia—precisely because they knew that NATO’s major Western European members likely lacked both the capability and the will to confront Moscow if needed. While the new members’ contributions may have had value, the relatively small size of their economies made substantial financial burden-sharing mathematically impossible. It should have come as no surprise that Americans would later wonder why their share of NATO’s upkeep should continue to grow—and how this has fueled a narrative in the United States that America’s NATO allies are “freeloaders.” In a series of tweets over the past two years, President Trump has suggested that continuation of American security guarantees to European partners rests, in part, not only on their increased defense spending but in taking actions on trade that benefit the U.S. economy, in order to justify American defense expenditures on their behalf—introducing a markedly more transactional tone into alliance commitments.

EVEN AS the absolute share of U.S. spending for NATO increased after the Cold War, the argument was put forward that Americans should not view this as a matter of dollars and cents but as an investment in spreading and sustaining liberal values and democratic governance. In the 2002 Wriston Lecture explaining the Bush administration’s National Security Strategy, Condoleezza Rice made the case why nations like the United States would have to bear greater burdens in order to create and sustain the balance of power that would favor freedom and the expansion of democracy. When it came to NATO, writing in these pages fifteen years ago, Radek Sikorski defined the alliance as the armed guarantor and defender of Western civilization.

If post-Cold War expansion of NATO was supposed to solidify the triumph of liberal democracy throughout the continent, then, as Celeste Wallander has written, “NATO is in peril” as “[m]ultiple members are dismantling the institutions and practices of liberal democracy...” Indeed, the nongovernmental advocacy group Freedom House rates Turkey, a key member of NATO and one of its largest contributors in military power, as “not free.” Freedom House describes two other NATO members as only “partly free” and charts a dramatic decline in commitment to democratic governance and liberal values across central Europe. A widely-cited televised exchange between Péter Szijjártó, the Hungarian foreign minister, and bbc News presenter Emily Maitlis in late June 2018 laid bare the growing divide between and within Euro-Atlantic societies over democracy and democratic values amid a contest between liberal internationalism and populist nationalism. Even in legacy NATO nations, populist parties with antiliberal, authoritarian tendencies have been gaining in strength.

What has happened? What to make, in the years after 1989, of repeated pledges and commitments to democracy and “shared European values” on the part of Central and Eastern European political leaders and parties that deployed such rhetoric to support their applications for EU and NATO membership? For one, contrary to what many claimed at the time, Central European experiences with democracy between World War I and World War II may not have created a sufficient foundation for rapid democratization after the Cold War. Realistically, there was likely very little continuity between halting interwar efforts to create liberal polities—only Czechoslovakia survived as a functional democracy until its destruction by Nazi Germany in 1939—and the post-Soviet successor states. A thirty-year-old Czech parliamentarian who watched Hitler’s stormtroopers march into Prague in 1939 would have been an eighty-year-old retiree (if still alive at all) during the 1989 Velvet Revolution. Even with a smattering of interwar survivors plus the assistance of emigres and their returning descendants, notably in the Baltic States, the process of creating sustainable democracies would be a generational project. Running the hardware of democracy, in the form of democratic institutions, without the software of a democratic political culture has rarely succeeded.