WASHINGTON — President Trump said he is considering withdrawing the United States from NATO. Congress passed a law in 2023 barring the president from leaving the alliance without Senate approval.

Trump asserted he has the authority to act alone. "I don't need Congress for that decision. I can make that decision myself," Trump said. The 2023 provision, included in the National Defense Authorization Act for fiscal year 2024, states that the president shall not suspend, terminate, denounce, or withdraw the U.S. from the North Atlantic Treaty except with the advice and consent of the Senate or by an Act of Congress. Senators Tim Kaine and Marco Rubio were the lead sponsors of the provision, according to public records.

Trump has criticized the defense spending and contributions of NATO member countries as insufficient. During his 2024 presidential campaign, he pressured members to increase defense spending and pledged not to withdraw the U.S. from the alliance if other countries raised their contributions. NATO member countries agreed to increase their defense spending following those campaign proposals.

During the war with Iran, some NATO allies denied the U.S. permission to use their airspace or airfields, and member countries resisted Trump's calls to send ships to reopen the Strait of Hormuz. Rubio, now serving as Secretary of State, said that if the U.S. cannot use military bases in Europe during its war with Iran, then membership in NATO must be reconsidered. "Unfortunately, we are going to have to reexamine whether or not this alliance, that has served this country well for a while, is still serving that purpose, or is it now become a one-way street?" Rubio said.

Rubio also said, "After this conflict is concluded, we are going to have to reexamine that relationship. We're going to have to reexamine the value of NATO and that alliance for our country. Ultimately, that's a decision for the president to make, and he'll have to make it."

Senate Minority Leader Chuck Schumer said the Senate will not vote to leave NATO and abandon allies because the president is upset that they would not support his war. The Senate Democratic caucus comprises 47 members.

The U.S. has taken on a smaller role in NATO military exercises as the administration has pressured European nations to increase defense spending. Lawmakers expressed concern that Trump could attempt to withdraw the U.S. from NATO if he returned to office, prompting Congress in 2023 to approve legislation preventing the president from doing so unilaterally.

NATO, the North Atlantic Treaty Organization, is a defensive alliance formed in 1949 with 12 member countries. It has since expanded to 32 members, with Finland joining in 2023 and Sweden in 2024. The alliance aims to guarantee the freedom and security of its members through political and military means. Article 5 of the North Atlantic Treaty states that an attack on one ally is considered an attack on all allies. Article 13 states that a member country may withdraw one year after providing a notice of denunciation to the U.S. government.