U.S. President Donald Trump has declared he is “without question” considering pulling the United States out of NATO, escalating a confrontation with Western allies that a former senior American diplomat warns has pushed the 77-year-old alliance into the worst crisis of its existence.
The threat, sharpened by NATO member states’ refusal to join Washington’s ongoing military campaign against Iran, has set up a potential constitutional showdown and cast deep uncertainty over the future of the world’s most powerful military alliance.
A War NATO Didn’t Sign Up For:
Trump launched the assault on Iran on February 28 alongside Israeli Prime Minister Benjamin Netanyahu — without consulting NATO allies and without their blessing. More than a month into the conflict, the regime change both leaders sought remains elusive.
Instead, Tehran’s countermove — shutting the Strait of Hormuz — has triggered a global oil price surge, a worldwide shortage of fertiliser and other essential goods, and mounting fears of a worldwide recession. Several European allies have gone further than mere non-participation, declaring the U.S.-Israeli offensive illegal and withholding overflight rights and access to military bases on their territory.
Trump’s response has been characteristically blunt. In an interview published Wednesday, April 1, he told The Telegraph the question of NATO was “beyond reconsideration” and that he had never been “swayed” by the alliance. He signalled he would air his grievances in a nationally televised address Wednesday evening.
“The Worst Crisis NATO Has Ever Confronted”
The language alarmed Ivo Daalder, who served as the U.S. permanent representative at NATO headquarters from 2009 to 2013.
“This is by far the worst crisis NATO has ever confronted,” Daalder wrote in an online commentary. “Military alliances are, at their core, based on trust: the confidence that if I am attacked, you will come help defend. It’s hard to see how any European country will now be able and willing to trust the United States to come to its defence.”
Daalder also noted that even short of a formal withdrawal, Trump possesses significant tools to hollow out the alliance from within — including pulling U.S. troops, removing American personnel from the NATO command structure, and refusing to respond to an attack on a member state, all of which would be “perfectly legal.”
Starmer Holds Firm; Rutte Flatters
The sharpest personal barbs have been reserved for Britain. Trump mocked the UK directly, telling The Telegraph: “You don’t even have a navy. You’re too old and had aircraft carriers that didn’t work.”
Prime Minister Keir Starmer brushed aside the taunts as “noise,” reaffirming that “NATO is the single most effective military alliance the world has ever seen,” and drawing a firm line on Iran: “This is not our war, and we’re not going to get dragged into it.”
NATO Secretary General Mark Rutte has taken the opposite approach — going out of his way to flatter Trump and even offering rhetorical support for the Iran war, a position that puts him at odds with nearly all of the alliance’s other 31 members.
Iran Strongly Denies Trump’s Ceasefire Request—The Latest Updates
European allies have simultaneously tried to future-proof the bloc, raising defence spending and — with diminishing returns — lobbying Washington to sustain support for Ukraine against Russia’s ongoing aggression.
Any formal U.S. withdrawal from NATO faces a significant legal obstacle. In 2024, Congress passed the National Defence Authorization Act (NDAA), barring any president from unilaterally exiting NATO without either a two-thirds Senate majority or an act of Congress. The legislation also prohibits using federal funds to facilitate a withdrawal — a provision co-sponsored by Senator Marco Rubio.
A withdrawal attempt would almost certainly trigger a constitutional crisis destined for the U.S. Supreme Court — a court with an established track record of deferring to the executive branch on foreign policy matters.
Legal analysts, however, caution that formal exit is only one path to NATO’s effective unravelling. “Other presidents have withdrawn from treaties,” Daalder noted, warning that Trump could achieve much the same outcome through deliberate inaction and institutional disengagement — without ever formally signing a withdrawal letter.