United States President Donald Trump's U-turns have driven Nato to an existential crisis. Between doubts over the continuation of American involvement and pressure for European autonomy, the future of the organisation, key for transatlantic security, has never seemed so uncertain.
An article on the home page of the North Atlantic Treaty Organisation (Nato) is illustrated with an image of the Ukrainian flag alongside the Nato flag – the blue and yellow side by side with the compass rose on its blue background, representing the Atlantic Ocean and the direction towards peace.
"Nato condemns Russia's war against Ukraine in the strongest terms. The Alliance remains steadfast in its support for Ukraine, helping to uphold its fundamental right to self-defence," reads the text.
However, in recent weeks the actions of one member – its main contributor – have seemed distinctly out of step with that statement.
Trump's reversals of the US position on Ukraine and the American rapprochement with Moscow represent an ideological break with Nato, in which Washington has always taken the leading role.
Created in 1949 during the Cold War, the political-military alliance that brings together 32 countries was founded on the need to guard against the expansion of the Soviet Union.
Although following the collapse of the USSR the organisation expanded its missions to include peacekeeping operations, since 2022 Russia has once again been designated a "threat" in the organisation's "strategic concept", which defines its doctrine.
Foundations of the Alliance shaken
With the US recently appearing more aligned with Russia than with its allies, this paradox raises questions about the future of the organisation. Trump has been increasingly critical of Nato, throughout his campaign and since his election, and has frequently cast doubt on his country's commitment to it.
During his speech at the Munich Security Conference in mid-February, US vice-president JD Vance urged Europeans to take their defence into their own hands. At the same time, from Warsaw, US defence secretary Pete Hegseth called on Europe to "invest, because you can't assume that the American presence will last forever".
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On 6 March, Trump questioned the solidarity of his allies: "My biggest problem with Nato is that if the United States had a problem and we called France or other countries that I won't name and said we've got a problem, do you think they would come and help us, as they're supposed to? I'm not sure."
Nato's Article 5 states that if a Nato country is the victim of an armed attack, this will be considered an attack on all members, all of whom will come to its aid, by any means deemed necessary including the use of armed force.
To date, the only time Article 5 has been invoked was by the US after the 9/11 attacks, which led to Nato's intervention in Afghanistan.
"For the time being, there has been no statement from the Trump administration calling into question the foundation of the Alliance, Article 5," stressed Amélie Zima, a researcher at the French Institute of International Relations (Ifri) and head of the European and Transatlantic Security Programme.
Article 5 is the cornerstone of the Nato edifice. "At a recent press conference, a journalist in the Oval Office asked Donald Trump if he would defend Poland. He immediately replied ‘yes, we are committed’. He was then asked the same question about the Baltic States. There he made a sort of grimace, believing that the matter was more complex, but he concluded all the same 'we are committed’," Zima added.
For its part, Nato is playing down any fears. "The transatlantic partnership remains the cornerstone of our Alliance," said the organisation's secretary-general Mark Rutte on 6 March, asserting that he had received guarantees from the US regarding its obligations.
At the same time, he called on Europeans to follow the example of Warsaw, which spends 4.7 percent of its GDP on defence.
"If you look at the spirit of the statements and Trump's pivot towards Russia, there is clearly a doubt that has been introduced," said Fabrice Pothier, former director of foresight at Nato from 2010 to 2016.
'Trump has cast doubt on Nato's reliability'
While fears of American disengagement are tangible, for Alexis Vahlas, director of a master's degree in European security at Sciences Po Strasbourg and a former Nato political adviser, this remains unlikely. According to him: "Nato remains a lever of influence and an essential interoperability tool for the United States."
But the unpredictable nature of the Trump administration means that all scenarios have to be considered. Could Nato function without the US or with less American involvement? Given that the country accounts for around 70 percent of Nato's military spending and that Article 5 is based on the premise of American military strength – particularly its nuclear arsenal – this would represent an unprecedented upheaval for the Alliance, which would consequently lose much of its credibility.
On 7 March, a Swedish media report quoting unnamed Nato sources indicated that the US had informed its Nato allies of its decision to stop participating in the planning of future military exercises in Europe from 1 January 2026. This information has not been confirmed.
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A US military source quoted by American military newspaper Stars and Stripes then said on 10 March that Nato was "continuing to prepare for military exercises involving the United States this year and beyond".
Amidst these contradictory statements, General Jean-Paul Paloméros, former Nato Supreme Allied Commander Transformation, told RFI: "These exercises are fundamental because they are representative of the Alliance's ability to fulfil its collective defence mission. If there are no more exercises, there is no longer any demonstration of credibility and joint training. That is Nato's great strength."
'A credible alternative'
"Today, there is a feeling of anxiety that is leading to a dual attitude," says Vahlas. On the one hand, it is a question of trying to preserve Western cohesion, while on the other, the 23 EU Member States who are Nato members – Austria, Ireland, Cyprus and Malta are not – are preparing to rely more on their own defence structures.
Brussels has validated the ReArm Europe plan, mobilising some €800 billion for European defence. "But there is no exclusivism," insists Valhas. In other words, the idea is to keep both mechanisms operational: to safeguard Nato as far as possible, while also strengthening the European alternative.
"Nato is not necessarily dead as an organisation, but it is less reliable, so we need to create an alternative that is sufficiently credible," said Pothier, who believes this alternative is being built outside the usual frameworks of European security – Nato and the EU – and instead, around a coalition of key countries.
"American developments, both in terms of support for Ukraine and rapprochement with Russia, and with the introduction of the transactional nature of the security guarantee, obviously represent a challenge for the transatlantic Alliance in a context where the threat is greater than at any time since the Cold War. But this does not prevent Nato from remaining a forum for political consultation, a planning framework for deterrence and defence, and interoperability for our armies," said Muriel Domenach, former French ambassador to Nato.
"While we are talking, Europe's armies are working within the Nato framework, and this cooperation is useful whatever the framework – EU, Nato or ad hoc," she added.
Previous crises
This is not the first time Nato's existence has been called into question. During his first electoral campaign in 2016, Trump deemed the organisation "obsolete" – before then reversing his position.
In 2019, Emmanuel Macron called the organisation "brain dead", while in the same year, the US decided to unilaterally withdraw its troops from Syria. France in fact left Nato's integrated command in 1966, with General de Gaulle preferring to maintain strategic independence from the US – although it was reinstated in 2009, under Nicolas Sarkozy.
"Nato has already been through some major crises," said Zima. "In the 1960s, when we moved from the doctrine of massive retaliation to a graduated response, De Gaulle was already expressing doubts about the Americans‘ willingness to defend Europe and, in particular, to use nuclear weapons."
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But the invasion of Ukraine in 2022, and the need to support the country, gave new weight to the organisation.
Natalia Pouzyreff, co-chair of the French delegation to the Nato Parliamentary Assembly, explained: "It is on this issue that the Europeans want to re-engage in dialogue with the United States. For us, there is a continuum. Ukraine is our shield and it is Europe's shield, and if Europe is not secure, that is not good for the Americans."
The Trump administration's stance, however, has clearly deviated from the values promoted by the organisation: freedom, democracy, the rule of law. "There have always been deviations, such as with Viktor Orban's Hungary or Turkey, but this is the first time that these deviations have been made by the world's leading political and military power," said Zima.
A Nato summit is scheduled for June 2025 in The Hague. Could there be a change in the organisation's strategic concept, in which Russia would no longer be designated "the most important principal threat" to the Allies?
"If the Americans were to push to institutionalise their position, I think we could be heading for a real institutional crisis," says Pothier. "It's one thing to have a spirit that is no longer that of transatlantic concord, but it's quite another to put it into the very letter of the institution."
This article has been adapted from the original version in French.
