After talks with NATO Secretary-General Mark Rutte, on Wednesday, Donald Trump once again suggested the US could leave the trans-Atlantic alliance.

Trump has previously threatened to leave NATO and often said that he would abandon allies who don’t spend enough on their military budgets.

But can he actually do it?

Not easily. In 2023, the US Congress passed a law blocking any president from withdrawing from NATO without congressional approval.

NATO, founded in 1949, is built on a mutual defence clause, under which an attack on one member is treated as an attack on all. This clause has been invoked only once, after the 9/11 attacks in 2001, when all NATO members at the time supported the US.

Trump’s frustration stems from the Iran war, where he has accused NATO members of not supporting efforts to reopen the Strait of Hormuz.

While Trump can threaten to leave NATO, any actual withdrawal would require Congress approval, which could be a major hurdle.

Published on April 9, 2026