Trump Threatens to Pull U.S. Out of NATO Amid Fallout Over Iran War. Can He Legally Do That?

President Trump said he is "beyond reconsideration" about withdrawing the U.S. from NATO after European allies declined to join the Iran war, with Secretary of State Marco Rubio echoing calls to "re-examine" the alliance after the conflict ends. Trump singled out the U.K. and Spain for refusing to provide military bases or airspace for U.S. operations against Iran, calling NATO a "paper tiger" and criticizing British Prime Minister Keir Starmer's refusal to actively participate. The 2024 National Defense Authorization Act requires a two-thirds Senate supermajority or an act of Congress to withdraw from NATO, but legal experts say Trump could attempt to circumvent that restriction by invoking presidential authority over foreign policy, potentially triggering a constitutional confrontation with Congress. Curtis Bradley of the University of Chicago noted the Supreme Court has often sided with the Trump Administration, which could complicate any congressional lawsuit, though contractors with NATO ties might also have legal grounds to challenge a withdrawal. Despite Trump's leverage and repeated threats, experts said a formal exit remains unlikely and continued tensions are a more probable outcome.