President Trump is threatening to pull the United States out of NATO over its members’ refusal to join the U.S.-Israeli war effort against Iran—an effort undertaken with no prior ally consultation. “Without the United States, there is no NATO,” warned Secretary of State Marco Rubio. “An alliance has to be mutually beneficial. It cannot be a one-way street. Let’s hope we can fix it.
But can we fix it? NATO Secretary-General Mark Rutte, an accomplished Trump whisperer, insists all will be fine. The European allies “are doing everything the United States is asking,” he offered last Thursday, implausibly. But with Washington’s 77-year commitment to NATO’s Article 5 collective defense principle now subordinated to an “America First” duty to do what the president wants, when he wants it, Europe’s least bad option may well be to go its own way. Europe should begin building its own integrated nuclear deterrent and unified combat capability—either inside or outside NATO—with a new intra-European “Article 5.” Whereas an alliance without U.S. participation will clearly be less powerful, a European grouping without a credible mutual defense trigger would invite aggression from Russia and other hostile powers.
To be clear, leaving NATO would be a bad U.S. decision. This is not a matter of liberal idealism or Cold War nostalgia. The only time Article 5 has ever been invoked was by America’s NATO allies, in solidarity with the United States after the September 11, 2001, al-Qaeda attacks on New York and Washington. More importantly, NATO remains the least costly mechanism the U.S. has for preventing the emergence of a hostile hegemon in Europe while preserving forward military access, intelligence sharing, and political leverage over the world’s richest and most advanced states. But the challenge of sustaining NATO extends well beyond managing Trump.
The president’s repeated claims that the European Union was created to “screw the U.S. on trade” are baseless, but it is important to understand NATO’s role in the development of the union—a union that has long aspired to geopolitical power without a commensurate homegrown military foundation. By popular account, NATO’s creation was a U.S. initiative in the wake of World War II—the centerpiece of a new grand strategy of “containing” the Soviet Union. Yet George Kennan, containment’s earliest architect at the State Department, opposed the creation of a military alliance. He sought instead to make a bold West European reconstruction program the heart of his security concept.
It was, in fact, France, Britain, Belgium, and the Netherlands that were the driving forces behind a transatlantic military alliance. Their argument was that the Marshall Plan’s blueprint for integrating Europe’s economies—which tied their security to revived German production of coal, steel, and industrial goods—was dangerous without American guarantees against both German and Russian aggression. Although the Truman administration launched the Marshall Plan as an alternative to a continued U.S. military presence in Europe, it ended up expanding and entrenching one. NATO became the military guarantor of reconstruction, and it has remained, decade after decade, the well-armed watchman for the ongoing business of European integration. American frustration with bearing the greater part of the associated cost predates Trump’s first term, having begun with the Eisenhower administration.
Today’s crisis in NATO is not just a product of Trump’s politics—it reflects deeper structural tensions embedded in the alliance’s post-Cold War evolution. Following the collapse of the Soviet Union in 1991, the Clinton administration faced a hugely consequential decision: whether to keep NATO and its composition as it was, to disband the alliance (like the Warsaw Pact), to replace it with a body that included Russia, or to expand it—perhaps up to Russia’s borders. Counterfactuals have limits, but post-Cold War history unfolded largely as Kennan—opining well into his 90s—warned it would under Clinton’s chosen option: expansion.
Clinton was a consummate political salesman. Yet it proved impossible simultaneously to convince East Europeans that NATO would protect them from Russia, to convince the Russians that expansion had nothing to do with them, and to convince Americans that expansion would be cheap—since NATO had no enemy.
In 1997, Kennan warned that “expanding NATO would be the most fateful error of American policy in the entire post-cold-war era.” He predicted it would “inflame nationalistic, anti-Western and militaristic tendencies in Russian opinion,” “have an adverse effect on the development of Russian democracy,” “restore the atmosphere of cold war to East-West relations,” and “impel Russian foreign policy in directions decidedly not to our liking.” Compare these predictions with those of NATO expansion’s most prominent advocate in the State Department. “[Y]ears from now,” Richard Holbrooke wrote in 1998, “people will look back at the debate and wonder what all the fuss was about. They will notice that nothing has changed in Russia’s relationship with the West.” Holbrooke’s confidence was profoundly misplaced.
NATO’s membership has doubled since 1999, from 16 to 32. There are two standard defenses of the enlargement. One is that it was intended only to stabilize Eastern Europe politically. NATO never had plans, or even the capacity, to invade Russia, and so its expansion was never more than a pretext for Russian aggression. But this argument misses the point. The issue was never invasion, but the behavior of border states acting more confrontationally under the assumption of automatic U.S. backing. In 2015, for example, Turkey shot down a Russian fighter jet that had crossed briefly into its airspace from Syria, where it was bombing opponents of the Assad regime. Turkey could claim self-defense and lack of territorial ambition, but it also acted knowing it had a call on Article 5 support. “Turkish airspace … is NATO airspace,” Ankara declared afterward. Russia took notice. “Turkey has not set itself up” as the actor, “but the North Atlantic alliance as a whole,” observed then-Prime Minister Dmitry Medvedev. “This is extremely irresponsible.” It is difficult, if not impossible, to imagine Turkey taking such radical action absent the belief that Washington had its back.
The second defense of expansion is that, absent forward alliance guarantees, Russia would be free to overrun its neighbors. But this rests on a highly compressed view of how Russian power is actually exercised. Russian interventions have not taken the form of sudden mass invasions; they have entailed political crises, force mobilizations, and escalating signals that unfold over weeks or months. The United States possesses unmatched intelligence capabilities and global power-projection forces. It does not require permanent alliance expansion to detect emerging threats or to respond decisively once they become clear.
Seen this way, the choice facing the United States in the 1990s was not between expansion and insecurity, but between competing models of post-Cold War order—one aiming at consolidating victory, the other at advancing the mothballed “One World” policy vison developed under Franklin Roosevelt. Neither model was without risk, but it cannot be ignored that the choice of the former was a factor in the creation of dangerous Russian counter-alliances in Asia and the Middle East.
A final problem with the NATO status quo is that too few Americans understand what their country’s membership entails. A 2024 Pew study found that only 30 percent of Americans could correctly identify elementary facts about NATO’s membership and purpose, while 31 percent could not answer any basic questions correctly. This ignorance creates political constraints for any president seeking to justify why the United States must fight to defend, say, Latvia or Montenegro.
Trump’s threats to withdraw from NATO are rash and misguided. Nonetheless, the U.S. desire to shift resources away from European defense is longstanding and, given mounting pressures in the Middle East and Asia, likely to intensify. It is therefore high time for Europe to extend its political and economic union into a credible military one.