NATO leaders are gathering in Ankara to confront US‑Europe tensions, address defence shortfalls, and bolster Ukraine’s military resilience.
The war in Ukraine and the fallout from the Iran conflict will dominate the NATO summit this week. Even before Secretary General Mark Rutte took to the stage on Tuesday, NATO’s most powerful individual had already set the tone.
President Donald Trump described the current relationship as “ridiculous” for the US to continue a one‑sided path, adding that “they were not there for us.”
Thirty‑two leaders of the transatlantic alliance are meeting in Ankara for a two‑day summit beginning Tuesday. The strained relationship between NATO members and the United States now stands as the alliance’s greatest challenge, casting a shadow over its future.
The alliance says the summit will prioritize three goals: boosting defense spending, expanding Europe’s defense industry, and sustaining long‑term military aid for Ukraine. This gathering follows last year’s commitment by allies to spend the equivalent of 5 % of GDP on defense, with European members and Canada raising their outlays by $139 billion in nominal terms during 2025 alone.
Nevertheless, discussions are being clouded by President Trump’s warnings that the US might exit NATO and his intention to relocate troops and weapons from Europe. On May 1 the Pentagon confirmed the withdrawal of roughly 5,000 service members from Germany, citing a “thorough review of the Department’s force posture in Europe.”
“I don’t think the alliance is at a breaking point,” said Ian Lesser, a distinguished fellow at the German Marshall Fund of the United States. “But it is entering a period of profound adjustment.”
Trump’s skepticism toward NATO is not new, but the recent clash with Iran has intensified friction within the alliance. He has repeatedly criticized European partners for refusing military backing, especially their refusal to join efforts to reopen the Strait of Hormuz.
A further source of tension is defense spending. On Thursday President Trump denounced the alliance as “ridiculous,” arguing that the United States spends more on NATO than any other nation to protect allies “without getting any benefit from doing so.”
Analysts note that while the US has shifted its stance on NATO, an actual withdrawal is unlikely due to legal and political hurdles, particularly as the nation gears up for midterm elections that will decide control of Congress.
Formally exiting NATO would require a two‑thirds Senate vote or an act of Congress—outcomes that appear unlikely anytime soon, as the alliance retains strong bipartisan support on Capitol Hill. “It’s in the US interest to stay engaged in Europe’s security and maintain a key role in NATO – and this is a view shared on both aisles in Washington,” said Lesser.
Europeans have largely abandoned the hope of restoring the deep trust that characterized the alliance in previous decades, but they still hope the summit will provide an opportunity for planning, according to Sophia Besch, a senior fellow in the Europe Programme at the Carnegie Endowment for International Peace.
“The one thing they still dare hope for is greater predictability,” Besch said. “They have accepted that the American commitment to Europe is changing; what they want is a more orderly version of the transition. The fear behind this is well‑founded: a botched handover from a US‑led to a Europe‑led NATO would create a deterrence and defense gap.”
Even amid worries about shrinking US backing, European allies would not be left defenseless. Russia’s invasion of Ukraine revealed both the fragility of Europe’s defense industry and how heavily many NATO members rely on Washington for critical capabilities. Ongoing transatlantic friction—ranging from internal NATO disputes to Trump’s threats concerning Greenland—has accelerated the drive for greater European strategic autonomy. Consequently, European defense spending climbed by 62 % between 2020 and 2025.
Significant capability gaps persist. The International Institute for Security Studies (IISS) reports that European nations still depend heavily on the United States for long‑range strike systems, intelligence, surveillance and reconnaissance, satellite assets, logistics, and integrated air and missile defense.
Addressing these shortfalls will be a prolonged endeavor. The IISS estimates that replacing the most critical US conventional capabilities would cost approximately $1 trillion and could take a decade or more. Europe’s defense industry also struggles to scale up production quickly, and many armed forces continue to grapple with recruitment and retention issues.
