ANALYSIS: Trump Threatens to Leave NATO — Congress Has Already Locked the Door

A well-established procedure since January 2025

The method is always the same. A unilateral decision. A sensational announcement. Immediate political impact. Then legal battles behind the scenes. On tariffs, Trump invoked the International Emergency Economic Powers Act—a 1977 law designed for national crises, not to reshape global trade through punitive tariffs. The Supreme Court, though reshaped by his own appointments, put the brakes on his most extreme measures.

On immigration, executive orders concerning birthright citizenship and expedited deportations were repeatedly struck down by federal courts—sometimes in record time, sometimes by judges Trump himself had appointed. Regarding federal funds, his administration attempted to freeze budget appropriations passed by Congress, in direct violation of Article I of the Constitution. The courts suspended the action.

Backing Down on Form, Winning on Substance

The genius—or the perversity—of this strategy is that Trump doesn’t need to win legally to win politically. Every threat to withdraw from NATO forces Europeans to increase their defense budgets. Every executive order that’s been struck down has already sown fear in the targeted communities. Every suspended tariff has already disrupted supply chains.

For him, the key is never a legal victory. It’s about shifting the line of what’s acceptable. In 2017, threatening to leave NATO was unthinkable. By 2025, it had become a bargaining chip. By 2026, it’s almost commonplace. The normalization of the unthinkable—that’s Trump’s real victory.

Taiwan, 1978: The First Crack

American history offers a troubling precedent. In 1978, Jimmy Carter unilaterally terminated the mutual defense treaty with Taiwan—a condition set by Beijing for the normalization of Sino-American relations. A group of Republican senators, led by Barry Goldwater, challenged the decision in court.

The Supreme Court at the time refused to rule on the merits of the case. The justices were divided on a fundamental question: Was this a “political question”—a dispute between constitutional branches that the judiciary is not meant to adjudicate? The majority ruled that it was, allowing the president to proceed without explicit judicial approval.

What Carter Had That Trump Does Not

But the comparison ends there. Carter was terminating a bilateral treaty with a country that the United States no longer recognized diplomatically. The geopolitical context justified the decision. Congress had not passed any specific law prohibiting such a withdrawal.

Trump, on the other hand, faces a legislative framework explicitly designed to block his path. The National Defense Authorization Act of 2023 is not a symbolic resolution. It is a federal law in force, signed by a president and passed by both chambers of Congress. Ignoring a law passed by Congress is not the same as exploiting a legal loophole—it is an act of constitutional defiance of an entirely different nature.

The Myth of the European Parasite

Trump portrays NATO as a financial burden that America alone bears on its shoulders. This interpretation deliberately ignores half the picture. The United States does indeed spend 3.4% of its GDP on defense, while most Europeans are still struggling to reach the 2% target agreed upon at the 2014 Wales Summit. On this specific point, Trump is right—and he is by no means the first U.S. president to complain about it.

Obama had already said so, albeit more diplomatically. Bush Sr. thought it. Clinton hinted at it. The difference is that Trump is turning a legitimate grievance into a tool of destruction.

What NATO Brings to the United States

For NATO is not an act of charity. It is a force multiplier that offers the United States what no amount of money alone can buy: military bases in 30 countries, interoperability with 31 allied armies, a shared intelligence network that spans the globe, and collective legitimacy for every intervention.

Ramstein, in Germany, is the nerve center of U.S. air operations in the Middle East. Sigonella, in Italy—the very same base that Rome has just closed—is the hub for U.S. drones in the Mediterranean and North Africa. Bases in Turkey, Poland, and Romania form a deterrence arc that allows the United States to project its power without having to deploy massive forces from its own territory.

Leaving NATO does not save money. It means losing the infrastructure that makes American power global.

The refusal that sparked the controversy

To understand Trump’s fury, we must look at what the Europeans actually refused. Not the Alliance. Not solidarity. A specific military operation. The Strait of Hormuz, overflights for strikes in Lebanon, access to bases for operations against Iran—this is not a NATO mission. It is an American-Israeli war in which Washington was asking the Europeans to get involved without having been consulted on the decision to launch it.

Article 5 of the North Atlantic Treaty—the one that commits members to collective defense—applies only when a member is attacked. No one has attacked the United States. Iran has not struck U.S. territory. What Trump was asking of the Europeans was not Atlantic solidarity—it was strategic subordination.

The European Calculation: Between Courage and Calculation

The Europeans who refused did not do so out of cowardice. They did so because participating in this war exposed them to Iranian retaliation without offering them any strategic benefit. Spain, whose Mediterranean trade depends on the stability of the Strait, made a sovereign calculation. France, which maintains diplomatic channels with Tehran, protected its room for maneuver.

And Italy—the very same Italy of Giorgia Meloni, the European leader closest to Trump—closed Sigonella. Even if Meloni says no, the message is unmistakable.

A Reluctant Arbiter on Foreign Policy Issues

The U.S. Constitution is an 18th-century document that did not anticipate the permanent military alliances of the 20th century. The power to enter into treaties is shared between the president and the Senate. But what about the power to terminate them? The Constitution is silent on this point. This silence is a loophole that every administration may attempt to exploit—and that every Congress attempts to close.

As recently as February 2026, the Congressional Budget Office acknowledged that the issue of unilateral withdrawal from a treaty “involves a long-standing and still unresolved debate” over the division of powers. After nearly 250 years of constitutional practice, America has still not settled this fundamental issue.

The Issue of “Standing”

Even if Trump were to push this through, someone would still need to have the legal standing to challenge his decision in court. An individual senator? A group of lawmakers? A foreign ally? The legal precedent is unclear. The Goldwater v. Carter precedent suggests that the Supreme Court might simply refuse to hear the case, referring the dispute back to the political sphere.

It is precisely this scenario that makes the 2023 law so important. By explicitly enacting legislation, Congress has transformed a matter of constitutional custom into a matter of positive law. Violating this law would no longer be exploiting a loophole—it would be violating a democratically enacted statute.

The Secretary of State’s Paradox

There is something dizzying about Marco Rubio’s career trajectory. In 2023, as a Florida senator, he co-sponsored a bill to prevent any president from unilaterally withdrawing from NATO. In 2026, as Trump’s Secretary of State, he publicly called for a “reassessment” of the U.S. role in the Alliance.

This is not a change of conviction. It is a career choice disguised as a strategic shift. Rubio knows full well that the bill he championed makes it impossible for his boss to do what he is threatening to do. But he also knows that, in the Trumpian universe, loyalty to the leader takes precedence over intellectual consistency.

The Complicit Silence of the Republican Senate

The most troubling thing isn’t Rubio. It’s the silence of the rest of the Republican Senate. The very same senators who voted for this law in 2023 are careful not to mention its existence in 2026. Not a single press release. Not a single press conference. Not a single call to order. Congress has forged a constitutional lock—and then collectively decided to look the other way while the president searches for the key.

This is the pathology of American democracy summed up in a single episode: institutions that are robust on paper, but elected officials too timid to activate them.

The Danger of Normalization

If you cry “wolf” too often, you’ll either end up not being listened to anymore, or you’ll actually let the wolf loose. Europeans are, as the magazine Le Point puts it, “Mithridatized”—immunized by habit against the venom of Trump’s threats. Each new provocation produces a little less adrenaline than the last.

This is a well-documented psychological mechanism. And that is precisely what makes it dangerous. Because the day Trump stops bluffing—or the day an even more radical successor takes his threats at face value—Europeans risk finding themselves without a Plan B, having mistaken the repetition of the threat for proof of its harmlessness.

Preparations That Speak Volumes

To their credit, some European governments have begun to act as if a U.S. withdrawal were not merely probable, but possible. Friedrich Merz’s Germany has allocated a special €500 billion fund for defense. France is pushing Europe toward an autonomous deterrent capability. Poland now devotes more than 4% of its GDP to its armed forces—a higher proportion than the United States.

These moves are not panic reactions. They are risk hedges. And the fact that they are accelerating precisely as Trump intensifies his threats suggests that, whether they have grown immune to them or not, Europeans are taking the possibility of a world without the U.S. security umbrella seriously.

The Geostrategic Gift of the Century

There is only one leader in the world for whom a U.S. withdrawal from NATO would be a total strategic victory: Vladimir Putin. Since at least 2007—since his Munich speech—the Russian president has regarded the Atlantic Alliance as the number one existential threat to his project of imperial restoration.

NATO is the reason Putin has been unable to annex the Baltic states the way he annexed Crimea. It is the reason his troops are bogged down in Ukraine rather than rolling toward Warsaw. Dismantling this alliance would achieve in a single administrative act what 75 years of Soviet and then Russian policy have never managed to accomplish.

The ultimate irony

And here is the irony that no one in Trump’s inner circle seems capable of voicing aloud: the president who presents himself as the toughest in the face of adversity, the supreme negotiator, the defender of American greatness, is in the process of handing his strategic rival—for free—the one thing the latter could not obtain by force.

Putin does not have the means to destroy NATO militarily. But if Trump does so politically, the result is the same. Russia regains its sphere of influence in Eastern Europe, American nuclear deterrence ceases to cover the continent, and the security architecture that has guaranteed 75 years of relative peace in Europe collapses without a single missile being fired.

A Constitutional Test That Goes Beyond the Alliance

The threat to NATO is not an isolated incident. It is a symptom of a profound transformation of the U.S. presidency. What is at stake here goes beyond military matters. It is the question of whether a U.S. president can govern by executive order, systematically bypassing Congress, treaties, and the courts.

On trade: unilateral executive orders. On immigration: unilateral executive orders. On federal funds: unilateral freeze. On military alliances: threat of unilateral withdrawal. The pattern is clear. This is not foreign policy—it is a theory of power according to which the elected president is the sole legitimate arbiter of the will of the people, and any institution that stands in his way is an obstacle to be eliminated.

Will the Constitution hold?

So far, the institutions have held firm. The Supreme Court has reined in the most extreme tariffs. Federal courts have blocked illegal deportations. The 2023 law exists and applies to everyone—including the president. But these safeguards only work if someone activates them.

A senator must file a lawsuit. A prosecutor must bring charges. A judge must accept the case. Every link in this chain is a human being facing considerable political pressure. And in a Republican Senate disciplined by the fear of a devastating presidential tweet, institutional courage is in short supply.

The Military Cost

Leaving NATO would mean closing or renegotiating access to dozens of military bases in Europe. Ramstein, Aviano, Lakenheath, Rota, Incirlik—each of these facilities is a hub in the United States’ global power-projection network. Rebuilding them elsewhere would cost hundreds of billions of dollars and take a decade.

Intelligence sharing with allies—particularly the Five Eyes network, which has been expanded to include NATO partners—would be severely compromised. Joint military exercises, which ensure the interoperability of forces in the event of a crisis, would cease. The U.S. ability to respond to an emergency in Europe, the Middle East, or Africa from forward operating bases would be irreversibly crippled.

The Diplomatic Cost

Beyond the military implications, there is the signal sent to the rest of the world. If America abandons its oldest and most powerful alliance, why would Japan still trust the U.S. nuclear umbrella? Why wouldn’t South Korea develop its own nuclear weapon? Why wouldn’t Taiwan negotiate directly with Beijing rather than wait for a protector who might never come?

Leaving NATO would not be an isolated act. It would be the first domino in the collapse of the entire system of alliances that makes the United States a global superpower rather than a regional power retreating behind its oceans.

Beyond Reaction: Building Resilience

The only intelligent response to a repeated threat is not outrage. It is preparation. Europeans must stop treating every Trump-style threat as a diplomatic crisis and start treating it for what it is: a structural warning sign about the long-term reliability of the American partner.

Not because Trump will actually leave NATO—the 2023 law, Article 13 of the treaty, and military realities make this scenario highly unlikely in the short term. But because the question is no longer “if” but “when” a U.S. president will decide that the political cost of the Alliance outweighs its domestic benefits.

Europe’s Moment of Truth

Europe has the economic means to defend itself on its own. Its combined GDP exceeds that of China. Its population is larger than that of the United States. Its industrial capabilities, if mobilized, could produce everything required for an autonomous defense—from ammunition to air defense systems to next-generation drones.

What is lacking is not money. It is not technology. It is the political will to overcome national rivalries in order to build a credible common defense. And paradoxically, it is Trump who could crystallize that will—not through his wisdom, but through the brutality of his threat.

What Will Happen—and What Won’t

Trump will not leave NATO. Not because he doesn’t want to—he probably does, at least in his moments of anger. But because Congress has locked the door, the Supreme Court won’t open this Pandora’s box, and even the hawks in his own party know that destroying the Atlantic Alliance would be an act of strategic self-mutilation.

What will happen, however, is that the threat will continue to have an effect. Europeans will increase their military budgets—which, in this case, is a good thing. The idea of an autonomous European defense will gain ground—which is a historical necessity. And Trump will reap the political credit for these changes without having had to carry out his threat.

The real danger is not what we think it is

The real danger is not a formal withdrawal from NATO. It is a gradual and silent disengagement—a reduction in troop levels at European bases, a slowdown in joint exercises, an erosion of intelligence sharing, and a calculated delay in invoking Article 5 in the event of a crisis. None of this requires a vote by Congress or a formal withdrawal from the treaty.

Trump may not leave NATO while simultaneously hollowing out the alliance. It is this scenario—one of gradual decay rather than a sudden break—that should keep European capitals awake at night. Not the tweets. Not the bombastic statements. The silence that will follow.

Signed, Jacques PJ Provost