For 75 years, European defence has rested on a simple premise: US power underwrites the continent’s security. American air and missile defences, intelligence, logistics, long-range strike capabilities and, above all, its nuclear umbrella have formed the backbone of Nato’s European deterrence.
In the face of Donald Trump, that is now being questioned. The US’s National Security Strategy last year explicitly stated that European countries must assume “significantly greater responsibility” for their own defences. This was not just diplomatic rhetoric: it reflects a major strategic shift.
China, not Russia, is now seen as America’s primary long-term competitor and Europe has to prepare for a future in which US support is increasingly reduced, delayed or politically conditional. War with Iran will have only further distracted the US from the needs of its European allies, and exposed the limits on Europe’s own military capabilities.
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Europe can’t replicate US power. However, it does not need to: the key task is deterrence, not substitution. Within three to five years, Europe must reach a credible threshold to convince Moscow that attacking Nato territory would be catastrophic.
That objective is narrow and achievable. Russia is unlikely to mount a large-scale conventional assault on Nato in the immediate term. But it will continue probing Europe through cyber operations, sabotage, political interference and calibrated military pressure, potentially testing cohesion along the alliance’s eastern flank.
Since 2022, European defence has fundamentally changed. Last year, the EU as a whole reached the target of 2 per cent of GDP spent on defence. The EU, along with the UK and Norway, now spend about €485bn a year on defence, compared with €305bn in 2022.
Preparation must extend far beyond procurement, however. Deterrence in this decade requires political cohesion and whole-of-society resilience. It is not merely a question of hardware. Air defence, munitions and manpower are necessary, but insufficient on their own.
Russia’s army – often described as battered and exhausted – can’t be underestimated. Despite an estimated 1.2 million casualties since it launched its full-scale invasion of Ukraine in February 2022, Moscow has replenished its ranks through continued recruitment. Russian artillery shell production has risen to more than 4 million rounds a year, supplemented by large imports from North Korea.
A Russian Yars intercontinental ballistic missile during a military parade in Moscow in May 2025 (Photo: Maxim Bogodvid/Host agency RIA Novosti)
Russia has also adapted to attritional warfare, has scaled up drone and missile production under sanctions and has embedded nuclear blackmail into its doctrine. It has integrated cyber operations, sabotage, organised crime networks and other forces as part of a continuum of conflict.
War has become central to Vladimir Putin’s survival. Defence spending now consumes roughly 7 per cent of Russian GDP and over a third of its federal spending. The country’s economy has been reorganised around sustained military production. Mobilisation and repression have reinforced internal control. Conflict is no longer an aberration; it is structural.
Meanwhile, Europe is still forced to depend heavily on US tech and expertise.
Air and missile defences remain patchy across much of the continent. The UK, strikingly, has almost no land-based air defence coverage. Intelligence, surveillance and reconnaissance are also US-dominated. American satellite architecture provides much of Nato’s high-end real-time battlefield awareness. Europe has national assets – France notably – and Germany is investing further, but integration is fragmented and nowhere near US scale.
Nuclear deterrence is the most sensitive gap. Britain and France maintain credible strategic arsenals but there is no clearly defined European nuclear doctrine beyond the US umbrella. Russia, meanwhile, has tactical nuclear weapons designed precisely for battlefield use – an escalation layer the UK eliminated decades ago to save money.
HMS ‘Vanguard’, a Royal Navy submarine that forms part of the UK’s nuclear deterrence (Photo by Jeff J Mitchell/Getty Images)
If Europe tried to fully replace the US, some experts believe defence spending would need to hit 8 to 10 per cent of GDP. This looks politically unrealistic. For two decades, European militaries optimised themselves for expeditionary missions and precision technology. The idea was that smaller, professional forces with advanced systems could compensate for scale.
The Ukraine war has challenged that assumption. Drones and AI adaptation are now crucial, with Ukraine ahead of both Europe and the US in battlefield innovation. Integrating Ukraine more closely into European defence structures is therefore not charity but strategic necessity.
The war in Ukraine has also demonstrated that mass matters. Ammunition stockpiles matter. Industrial capacity matters. Numbers matter.
The British Army has fallen below 70,000 personnel – the smallest since the eighteenth century, with nuclear deterrents absorbing roughly a quarter of the UK’s defence budget. Sustaining even limited deployments for extended periods of time would strain rotation capacity.
Across Europe, manpower remains a challenge. The problem is not an absence of capability, but a shortage of depth; the ability to sustain combat over time.
Ultimately, Europe’s biggest vulnerability may not be hardware but political will. Deterrence requires sustained investment over years, likely at the expense of other priorities. It may require higher taxes or constrained welfare spending. Few European leaders have explained this openly to their publics.
A soldier from the Norwegian army participating in the Cold Response 2022 military exercise, gathering around 30,000 troops from Nato member countries as well as Finland and Sweden (Photo: Yves Herman/File Photo)
In places like the Baltics, Nordics and Poland, proximity to Russia has created a “whole-of-society” resilience culture. Citizens understand the risk. Elsewhere, the political class remains more comfortable with negotiation and compromise than with preparing people for a future conflict.
Europe could deter Russia if investment continues and coordination deepens. But the most dangerous period is before that threshold is reached. Russia may look to test Nato cohesion through cyber operations or calibrated military intimidation. Nuclear signalling would also likely intensify.
Europe needs to prepare accordingly. It needs to continue and increase investing into manpower, air defence, munitions and mobility, as well as enhance intelligence integration. It needs to prepare its people.
Economically, this is achievable. The combined economy of Nato’s European members is roughly five times larger than Russia’s in purchasing power parity terms, and their troops exceed Russia’s military by several hundred thousand. The issue is coordination, political resolve and public consent.
The US’s security guarantees have been both shield and crutch. If they shrink or disappear entirely, Europe will face a difficult and dangerous period. The question isn’t whether Europe is capable, it is whether it is prepared to act before the risks of Russian aggression grow too great.
Katia Glod is the deputy director of foreign policy at the New Eurasian Strategies Centre