President Donald Trump ignited fresh concerns among NATO allies on Tuesday by casting doubt on the United States’ full commitment to the alliance’s core principle — Article 5, the collective defense clause. Speaking aboard Air Force One en route to The Hague, where he is attending the NATO summit, Trump offered a vague and qualified answer when asked if the U.S. would honor the obligation to defend another member in case of an attack.
“Depends on your definition. There are numerous definitions of Article 5,” Trump said, adding, “I’m committed to being their friends. I’m committed to saving lives.” The remarks, lacking a clear endorsement of the mutual-defense pledge, quickly reverberated through diplomatic channels and drew attention as the summit opened.
Article 5, which states that an attack against one NATO member is considered an attack against all, has only been invoked once — in support of the United States following the September 11, 2001 attacks. Trump’s comments come at a particularly sensitive time, as NATO seeks to project unity in the face of continued Russian aggression, instability in the Middle East, and growing cyber threats.
NATO Secretary-General Mark Rutte attempted to downplay the significance of Trump’s remarks, telling reporters that he had “no doubt” about America’s commitment to the alliance. “The United States is totally committed to NATO and to Article 5,” Rutte insisted. He also praised Trump’s leadership on defense spending and credited him for pressuring European allies to significantly increase their military budgets.
Trump is expected to use the summit to push NATO members toward adopting a new target: allocating 5% of their GDP to defense by 2035 — a dramatic increase from the current 2% guideline. According to sources close to the administration, the proposal has received mixed reactions in Europe but is gaining traction among NATO hawks.
While Trump’s call for more equitable burden-sharing aligns with his long-standing position, his reluctance to firmly commit to Article 5 raises concerns among allies who fear a weakening of NATO’s foundational guarantee. Critics argue that even rhetorical ambiguity could embolden adversaries and undermine deterrence.
Despite the controversy, the summit is proceeding with high-level discussions focused on strengthening the alliance’s eastern flank, addressing ongoing support for Ukraine, and preparing responses to hybrid threats from Russia and others. A joint declaration is expected by the end of the summit, potentially including the 5% spending target.
