The president’s confrontation with NATO hasn’t led to a major U.S. withdrawal. But a big troop cut remains an option, Pentagon sources say, and allies are preparing for a future less dependent on Washington.
Mihail Kogalniceanu Air Base in Romania was built to make Americans feel at home. Its streets are named Alabama, Ohio, Alaska and George Washington. The base has hosted U.S. troops since 1999 and supported America’s wars in Iraq and Afghanistan.
Last year, about half of the approximately 2,000 American troops in Romania, most of them living at the base, departed as the Trump administration began a radical realignment of the U.S. military presence in Europe. In Romania, a North Atlantic Treaty Organization country bordering Ukraine, the departures caused alarm: MK, as the base is known, sits on the alliance’s eastern flank at a time when Russian drones have repeatedly crossed into NATO territory.
But when Reuters visited MK in July, the base told a more complicated story about U.S. President Donald Trump’s effort to remake NATO. Nine U.S. KC-135 Stratotankers were parked there, deployed to refuel American jets and bombers during the Iran war. Their crews and support staff had partially offset the earlier troop departures, a reminder that Washington still relies heavily on European bases. More than two months later, the Stratotankers were still there.
That paradox sits at the center of Trump’s confrontation with the 32-nation alliance. He has threatened troop cuts, badgered allies over defense spending and denounced European governments for refusing to unconditionally support the U.S.-Israeli war against Iran. Yet a Reuters examination of U.S. military operations in Europe found that the Trump administration continues to invest in key NATO military facilities and is relying on them to project power across Europe, the Middle East and beyond.
To assess the effects of Trump’s pressure campaign on NATO, Reuters interviewed more than 50 current and former Western officials, military officers, diplomats and defense experts, including senior Trump administration officials, congressional aides, and former U.S. ambassadors to NATO. Reuters journalists also visited bases used by NATO in Romania and Estonia, and observed NATO military exercises off the coast of North Carolina.
The reporting revealed an alliance under strain though not yet broken. Nine current and former U.S. officials told Reuters that congressional Republicans and Democrats, along with powerful U.S. defense contractors with big European customers, have the political clout to block a U.S. withdrawal from NATO – something Trump has repeatedly threatened to do.
Yet Trump’s attacks are damaging the 77-year-old alliance in ways that European and American strategists alike say are difficult to reverse. Europe is increasingly questioning America’s reliability as a security partner, Reuters found, and those doubts are now shaping defense spending, weapons procurement and long-term security planning across the continent.
Many of those interviewed described a slump in transatlantic trust that has weakened NATO’s central deterrent: Article 5, the pledge that an armed attack on one member will be treated as an attack on all. A failing NATO led by an unreliable U.S. could be catastrophic for Europe’s security as the region confronts an aggressive and openly expansionist Russia along its eastern borders.
And even as military spending surges across NATO, at least eight member countries – including Canada, Poland, Denmark and Spain – are beginning to diversify away from their reliance on U.S. weapons, technology and defense companies, Reuters found. This suggests Trump’s campaign to force Europe to spend more on defense could ultimately backfire by prompting some allies to reduce their dependence on U.S. defense contractors and military technology.
“The pressure on Europe worked, but it created real uncertainty,” said J.C. Lintzenich, a senior U.S. military intelligence official who left government in February after advising top Pentagon officials, the Director of National Intelligence and policymakers in Congress. “Europe is spending more, taking defense more seriously, and accepting greater responsibility – that is a real success. But there is also genuine concern in Europe that the United States could abandon them.”
“President Trump has done more for NATO than anyone else,” said White House spokesperson Olivia Wales. “He will always unapologetically advance America’s interests.” While Trump has taken credit for the rise in European defense spending, it has also been fueled by Russia’s full-scale invasion of Ukraine in 2022, which has flattened cities, killed hundreds of thousands of people and sent millions fleeing across Europe.
“A strong alliance has allies that hold each other accountable,” Matthew Whitaker, U.S. ambassador to NATO, told Reuters. In a statement, NATO pointed to recent remarks by Secretary General Mark Rutte, who praised Trump for helping drive higher defense spending across the alliance.
But Trump’s ability to remake NATO has run up against significant constraints. Before leaving for a NATO ministerial meeting in Brussels in June, U.S. Defense Secretary Pete Hegseth had planned to announce a cut of roughly 25,000 U.S. troops in Europe, according to two U.S. officials. The proposed cuts – the scale of which has not been previously reported – would have pushed American force levels in Europe below a congressionally mandated 76,000-troop minimum signed into law last year.
Instead, Hegseth faced resistance within Trump’s own administration and arrived at NATO’s curved steel-and-glass headquarters in Brussels with a warning for allied defense ministers. The Pentagon would conduct a six-month review of America’s force posture in Europe, with particular scrutiny of countries that say “no, or maybe, or wait and see” when Washington needs support. “This will be a real review,” Hegseth said. “Some countries will fail.”
The Pentagon has been tight-lipped about the review, but in August it prepared a document with 57 questions for allies aimed at measuring their military, financial and ideological commitment to the U.S., according to a copy of the memo reviewed by Reuters. One question, for instance, asks whether a country has been “publicly supportive of U.S. foreign policy priorities.”
The review exposed a struggle in Washington over how far the U.S. can reduce its role in Europe without undercutting its own military reach. Five senior congressional aides – both Republicans and Democrats – told Reuters there was growing bipartisan distrust of Hegseth’s handling of NATO. One of the aides said Republican and Democratic senators were worried the Pentagon might announce “a move that might not be positive for NATO or even U.S. national security.”
One possible outcome of the force review, said three people familiar with the matter, is that Hegseth could propose the same number that he wanted to announce in June: a 25,000 cut.
The White House has said the six-month review will “ensure irreversible momentum toward a European-led defense of Europe.” The Pentagon and Hegseth didn’t respond to written requests for comment. But a senior Pentagon official told Reuters: “This is a serious review, designed to be rigorous, consultative and empirical.”
The U.S. has more than 81,000 military personnel in Europe, a number that fluctuates as troops rotate through the continent on deployments and exercises, according to government audits and congressional testimony reviewed by Reuters.
In the four years before Trump first took office in 2017, the U.S. averaged about 65,000 troops and other military personnel in Europe. That figure rose to 74,000 during his first term, then surged to 105,000 under former President Joe Biden after Russia’s full-scale invasion of Ukraine in 2022. By the time Trump returned to office in 2025, the number had fallen back to roughly current levels.
The battle over NATO is part of Trump’s broader upending of the international order the U.S. helped build after World War Two. His administration is challenging long-standing institutions, alliances and norms with a more transactional, “America First” approach that prizes U.S. dominance over treaties and multilateral cooperation. Previous Reuters reporting detailed Trump’s assault on the global justice system through crippling U.S. sanctions against the International Criminal Court and his scrambling of American diplomacy by hollowing out U.S. embassies and threatening friends and foes alike.
TROOPS AND TRUST
Most allies met Trump’s demands for higher defense spending, turning NATO’s potentially explosive Ankara summit in July into what Trump called “a very successful” meeting.
But the Pentagon’s six-month review remains the central uncertainty hanging over the alliance. Some European officials believe NATO’s military leadership can manage an eventual U.S. drawdown without exposing the continent’s vulnerabilities. Others fear the process could trigger a competition for Washington’s favor. In Romania and Poland, officials told Reuters they have lobbied discreetly but intensively to keep American troops on their territory.
“Why do all these countries want U.S. soldiers on their soil?” said George Scutaru, a Romanian defense expert and head of the New Strategy Center, a Bucharest think tank. “Because it’s the best deterrent – a human shield.”
The Iran war underscores how dependent Washington remains on European geography, even when relations with allies are strained.
Italy denied permission in late March for some U.S. military aircraft to land at the Sigonella air base in Sicily before heading to the Middle East, Reuters reported. But by late June, more than 500 U.S. military aircraft had transited Italian bases, including 343 through Sigonella and 211 through Aviano in the country’s north, many of them carrying munitions, according to a third U.S. official.
Even so, Trump attacked Italian Prime Minister Giorgia Meloni in a June 20 post on social media, saying “she wouldn’t even let us use Italy’s landing strips or runways, a great logistical inconvenience.” The Italian government didn’t respond to a request for comment.
Since 1949, NATO has been a cornerstone of American power, helping the U.S. to station forces across Europe, deter adversaries, project military strength and anchor a bloc of democratic allies. In return, Europe gained the protection of the world’s most powerful military, helping sustain an era of peace and prosperity unmatched in its modern history.
Europe is spending more, taking defense more seriously, and accepting greater responsibility – that is a real success. But there is also genuine concern in Europe that the United States could abandon them.
J.C. Lintzenich, former senior U.S. military intelligence official
For generations, that bargain enjoyed broad support across party lines in Washington. But not from Trump. His position – that other countries freeload off U.S. protection – has stayed remarkably consistent across four decades of public life.
“A lot of people are tired of watching other countries ripping off the United States,” he said in a 1987 interview on CNN. Allies had to pay up or “get out,” Trump said during his 2016 presidential campaign. “And if it breaks up NATO, it breaks up NATO.” In his first term, Trump demanded allies increase defense spending from 2% to 4% of gross domestic product. Just before returning to office in 2025, he pushed for 5%.
“If they don’t pay, I’m not going to defend them,” he told reporters in March 2025.
European allies and Canada spent 2.3% of their combined GDP on defense in 2025, according to NATO. All of them, apart from Spain, have agreed to spend 5% on defense and broader security-related investments by 2035.
Kay Bailey Hutchison, a former Republican U.S. senator who served as Trump’s ambassador to NATO in his first term, said Trump seems to believe that the U.S. gains more through his relationships with the leaders of rival powers such as Russia and China than through alliances such as NATO. “I always wanted the president to understand that if our long-term adversary is China, we need allies,” she said.
Despite those attacks on NATO, Trump has continued funding major infrastructure projects at European military facilities over his second term. In Spain, which Trump denounced at the Ankara summit as “a terrible partner in NATO” and “a wasted cause,” Washington has shown no sign of pulling back from Naval Station Rota or Moron Air Base.
In May and June alone, the U.S. announced reinforcement of aircraft facilities and $400 million in construction contracts to Spanish companies at Moron to maintain and improve the base over the next decade.
Rota and Moron are difficult to replace. They offer access to the Atlantic and Mediterranean and extend U.S. military power into the Middle East and North Africa. At a press conference at the Ankara summit, Spanish Prime Minister Pedro Sanchez said the deployment of American forces in Europe was a “sovereign decision” of the U.S. and that Spain’s military relations with it were “excellent.”
In Romania, the U.S. has invested more than $100 million in the ongoing expansion of Mihail Kogalniceanu Air Base, alongside a roughly $2.7 billion project funded by Romania that aims by 2040 to make the installation the largest NATO air base in Europe, with capacity for up to 20,000 personnel.
Trump slammed then-Prime Minister Keir Starmer in March over Britain’s limited support for U.S. strikes on Iran. But the U.S. is spending more than $4.2 billion on current and upcoming projects at seven air bases in Britain, according to a March presentation by a U.S. Air Force unit that manages base infrastructure. U.S. bombers have flown missions against Iranian targets from at least one of those British bases, reinforcing the strategic importance of Europe to U.S. military operations well beyond the continent.
But at least a dozen past and present officials from Europe, the U.S. and Canada cautioned that Trump doesn’t need to formally withdraw from NATO to hobble the alliance. His anti-NATO rhetoric alone might signal to Russian leader Vladimir Putin that the West is divided and more vulnerable than it appears.
Those officials said they fear Putin is testing that assumption with a wave of sabotage incidents across the continent, which European countries blame on Russia. They include, in August alone, an attempted drone attack on a German airport and a fire at a Polish drone factory.
In July, just two days after Reuters visited Romania’s MK Air Base, NATO scrambled Romanian fighter aircraft to intercept a Russian drone that had penetrated Romanian territory. It was shot down by a Romanian F-16 operating from another base. Two more drones, also believed to be Russian, were downed in the following days. Then, in late July, a Russian cruise missile landed in Poland, another front-line NATO ally.
Asked about the incidents in Germany, Poland and Romania, Russia’s ambassador to Belgium, Denis Gonchar, denied any Russian involvement and called them “dirty provocations” by Ukraine and others who wanted to “drag NATO and the European Union into a direct conflict with Russia.”
