What Next For Europe's Defence?

Illustration by Will Allen/Europinion

Donald Trump’s sweeping tariffs have shifted the news cycle away from the Ukraine War to the faltering global economy, sending stock valuations across the globe plummeting.

This has provided another American headache for European nations, with President of the European Commission Ursula von der Leyen threatening EU sanctions on American tech if tariff talks break down

This has distracted from the other headache Europe has been trying to medicate in 2025: what does the future of Europe’s defence look like without the United States as a reliable partner? 

Comments from White House officials have suggested the US is no longer fully committed to its underpinning role in European defence. JD Vance’s dressing down of European allies, and the White House signal group chat leak  revealed a deteriorating view towards European allies and the guarantees the United States currently provides, with Vance remarking how he “hated to bail Europe out again”. Trump has long toyed with a US withdrawal from the NATO alliance in a bid to encourage defence spending increases from its members. 

Even if the US does not formally withdraw from NATO, the confidence underpinning article 5 that the US will come to the aid of a fellow member under attack has been weakened. Trump has made comments that he would not protect NATO members who fail to pay into NATO, even encouraging Putin and Russia  to “do whatever they hell they want” to underpaying members. If the US was to conduct the military action it has floated in Greenland and thus effectively attack a fellow NATO member in Denmark, it seems implausible for NATO to carry on as an organisation with any credibility.

NATO chief Jens Stoltenberg had acknowledged the existential risk that the potential US withdrawal poses, while UK Prime Minister Keir Starmer has warned with the new US administration that “everything has changed” for European security.  

The European continent must now consider as a matter of urgency the future of its defence in the absence of a US security blanket. The European Commission’s White Paper recognises as much, stating “Europe faces a fundamental choice about its future”. So, what would this new era look like and what challenges would the continent face in forming a common defence against threats such as Putin’s Tsarist bloodlust? 

An immediate question would be what form the leadership of a new European defence would take. Keir Starmer and Emmanuel Macron have pivoted from their joint charm offensive on Trump to military figureheads for a new era in European defence. A so-called coalition of the willing between the two leaders has been formed as a result. Practically, these nations are the only two suitable leaders for a European defence from a deterrence perspective as they are the only two nuclear powers. Senior research fellow at Chatham House Marion Messmer argues a demonstration of “joint force, such as through a UK-French offer” is one of the few ways for Russia to take European deterrence seriously in the absence of the US. Despite the obvious caveat that the UK is no longer in the EU, Starmer has recognised the opportunity of leadership this presents for the country to rescue it from its relative geopolitical limbo in the post-Brexit world. His embrace of Volodymyr Zelenskyy in the aftermath of the infamous White House meeting in March positioned him as a statesman befitting the world stage. The UK’s nuclear deterrence programme Trident faces problems, however. It is heavily reliant on US hardware and maintenance, and has faced various technical issues, with the last two test firings in 2016 and 2024 both failing. France meanwhile has a rare nuclear independence from the United States, with its arsenal developed under Charles de Gaulle’s insistence on a sovereign nuclear deterrence. This has enabled Macron to suggest the idea of France becoming the continent's nuclear umbrella. However, the effectiveness of such a deterrence would be limited. France’s stockpile is only 5.5% the size of Russia’s, and a combined UK and France arsenal is only 20% the size of the US’s. 

Illustration by Will Allen/Europinion

Therefore, for this leadership and programme of deterrence to be effective, it would also have to incorporate the rest of the continent. As a result, they would need to overcome the existing roadblocks for a unified defence policy in Europe. One of these roadblocks is the deployment of a European peace keeping force in the event of a ceasefire agreement being reached in Ukraine. Macron and Starmer have both consistently suggested the idea of a European peacekeeping force in Ukraine to maintain a ceasefire. However, many European nations diverge from this view. Spanish Prime Minister Pedro Sanchez has expressed opposition to the idea, while German Chancellor Olaf Scholz described the peacekeeping force talk as “inappropriate”. Another is funding and defence spending. Hungary’s Prime Minister Viktor Orban consistently takes a hard line against European Union foreign policy and stoppers allocations of defence resources. His vetoing of an EU push to replace US military aid to Ukraine and criticism of European Union military support for Ukraine represents the challenge in maintaining a united front. A defence force  paralysed by a non-compliant member would weaken its credibility as an effective organisation and raise doubts over its unity. Additionally, the UK’s position as an outsider in the EU hamstrings its ability to influence nations on the continent. 

Perhaps the most fundamental obstacle to a united European defence front is the national sovereignty concessions member states would have to provide. The French national assembly vetoed an early concept of a European Community in 1954 for this very reason. Many countries view the relinquishing of control over defence spending and decision-making an unacceptable price to pay for a united European front. The idea of a future European Army was frequently used by the Vote Leave campaign in the 2016 Brexit referendum to stoke fears of Brussels taking further decision-making power away from Westminster. 

Despite the divergence in attitudes and power sharing, there is clear consensus of the need for a revaluation of how the continent defends itself. This view is supported by EU public opinion, with around 80% of EU citizens supporting a common defence policy, showing a strong backing for cooperation. The EU has recently unveiled a plan dubbed “Readiness 2030 Plan”, with the aim to allocate €800 billion for European defence infrastructure by 2030. This is to be achieved through offering loans for joint defence projects and suspending EU budget laws. The initiative contains plans to redirect existing cohesion funds to defence investments, lift European Investment Bank lending restrictions on defence firms and the creation of a savings union encouraging private investment in the defence sector. The view that an increase in defence spending is required is shared by most European nations. Polish President Andrej Duda announced in February plans to increase military spending to 4.7% of GDP, far exceeding the NATO target of 2%. Germany provides the most symbolic increase, recognising its long reluctance to increase military spending is now no longer compliant with the reality Europe faces. German lawmakers voted in March to exempt defence spending from its fiscal rules, creating a €500bn infrastructure fund. 

These increases in expenditure from European nations would be required to match the deficit in finance, infrastructure and troop numbers a US withdrawal would create. This replacement would not be impossible, but it would certainly require intense cooperation and financing. To replace the US in its military support for Ukraine for example, the EU would only have to spend another 0.12% of its GDP. This would only be one issue that Europe would face though. For example, the absence of access to military US bases on the continent would pose a serious challenge to any further military coordination and would require exceptional cooperation to mitigate. Additionally, it’s estimated that the continent would lose 300,000 allocated US troops for Russian attack on a European NATO country if they were to withdraw. There are also recent reports of Senior Defense Department officials considering withdrawing as many as 10,000 troops from Eastern Europe. These infrastructure and troop replacements would require intense cooperation and financing from European nations. This is something the EU’s “Readiness 2030 Plan” hopes to remedy, providing the necessary infrastructure to achieve the defence self-reliance it now desires. Once this is achieved, Europe Executive Director of IISS Ben Schreer argues Europe “could pose a serious conventional and … nuclear deterrent” to Russia.

The European continent faces leadership conundrums, decision-making sharing and divergence on attitudes should the US ultimately vacate its role as the great protector of Europe. But there is a clear desire within the continent to build a serious, self-reliant defence policy with or without the presence of the US. Importantly, there is a belief this is possible as expressed by Polish Prime Minister Donald Tusk: “Europe as a whole is truly capable of winning any military, financial, economic confrontation with Russia”