The likelihood of the United States withdrawing from the North Atlantic Treaty Organization (NATO) has increased to 15 percent, according to a prediction market on Polymarket. This surge is linked to escalating rhetoric from former President Donald Trump regarding the commitment of NATO allies.

Trump Reiterates Doubts About NATO

When asked if he would reconsider his stance on NATO, Trump stated, “Oh yes, I would say beyond reconsideration. I was never swayed by NATO.” This sentiment reflects years of criticism directed towards America’s European allies, urging them to increase defense spending and take greater responsibility for their own security.

Frustration Over Iran and the Strait of Hormuz

Trump has expressed particular frustration with NATO allies’ reluctance to participate in a potential U.S. military campaign against Iran. He has publicly called some allies “cowards” and demanded they assist with securing the Strait of Hormuz, a critical waterway for global energy supplies. He suggested allies either purchase U.S. oil or “go to the Strait of Hormuz…and just TAKE IT.”

Fluctuating Prediction Market Odds

The prediction market saw a significant spike in withdrawal odds in mid-December 2025, reaching approximately 20 percent. Odds later decreased to around 8 percent by late January 2026. A further increase to 16 percent occurred following Trump’s criticism of Denmark in mid-January, before a subsequent reversal at the Davos summit. The most recent and substantial climb began in late March 2026, driven by his dissatisfaction with the lack of support for the Iran campaign.

NATO's Collective Security and Current Challenges

NATO’s core principle is Article 5, which stipulates that an attack on one member is considered an attack on all. Recent missile and drone attacks targeting NATO member Turkey and a British military base in Cyprus have raised questions about the potential invocation of this collective security guarantee. However, the alliance has not intervened or indicated plans to do so.

Focus on Ukraine and Consensus-Based Decision Making

NATO Secretary-General Mark Rutte has primarily focused on Russia’s war against Ukraine, which borders four NATO countries. NATO operates on a consensus basis, requiring unanimous agreement from all 32 member states for any decision, including invoking Article 5.

Legislative Safeguards and Public Opinion

Legislation passed in December 2023, spearheaded by Senator Tim Kaine and Secretary of State Marco Rubio, prevents the President from unilaterally withdrawing the U.S. from NATO. Any withdrawal would require a two-thirds vote in the Senate or an Act of Congress.

According to the Ronald Reagan Institute’s latest National Defense Survey, 68 percent of Americans currently view NATO favorably, the highest percentage since 2018. A majority, three in four Americans, support maintaining or increasing U.S. support for the alliance, though opinions are sharply divided along party lines.