Recent statements by US Defence Secretary Hegseth at his first Ramstein format meeting, US Vice President Vance at the Munich Security Conference, and the clash between US President Trump and Ukrainian President Zelenskyy, have cast serious doubt on whether the current US administration will uphold security guarantees. Given these profound shifts in US policy, and the existential threat of another war on the continent, Europe, must manage its essential defence tasks (deterrence, defence and support to Ukraine) with limited or even no support from the US. A transition strategy into a European Way of War is needed. Besides a different approach to generating warfighting capabilities, industrial bases and spending money, this implies first and foremost a way of organising political leadership that ensures Europe’s security and defence. This transition would preferably take place in coordination with the US. But Europe needs to stand ready to go it alone.
Can’t buy love nor leadership
Thus far, some European leaders seem to have persuaded themselves that managing US withdrawal is a mix of money and material: Europe simply has to buy what it would otherwise lose. Demand will surely be there. Europe must prepare to replace three key elements: (a) US firepower, (b) US enablers or C4ISR (intelligence, surveillance, target acquisition, and reconnaissance), and (c) US nuclear deterrence.
Before buying kit, however, Europe must replace something harder to substitute: US political and military leadership. The US has been the centre of gravity due to its military and economic power, enabling NATO collective strategy and military operations. Without the ability and authority to lead, more weapons would be useless: who decides what to buy, based on which defence plans, and who authorises the use of weapons?
A European Way of War: building blocks
This US role, which allies happily accepted for decades, has created political, military and industrial path dependencies. As this path comes to an end, Europe must actively define its own way of war, i.e. a political and military strategy suitable to the available European posture, political coherence (or lack thereof), resources and geo-strategic realities. This implies a different approach to warfighting (including doctrine and concepts), industrial bases, and military cooperation that constitutes a profound change for Europe and requires significant resources.
Political governance: European not EU
Europe cannot implement an effective security strategy without more unified political leadership. This will be no single country, but a combination that reflects a balance between effectiveness and inclusiveness. Able and willing European countries will have to come together, also to exert influence over their respective regions, as some allies have diverging opinions on how to proceed, and towards which objective. A decision is needed on how authority and decision-making power can be split and shared. Such a governance format must certainly include Ukraine. The Paris leaders’ meetings on 16 and 19 February 2025 pointed towards an E5+ Format: France, Germany, Italy, Poland, the UK and potentially other nations, but also EU institutions where necessary, for example on policy coordination and alignment, finance instruments, and Single Market-related issues.
Military governance: Use what has worked in the past
Political objectives need to be turned into military options. Conversely, civilian leadership needs to have military options it can decide on. NATO can continue to provide the military governance and structures to generate these options and to interact with civilian leaders, even with an “empty chair” policy by the US. There is no need to create alternative structures. Instead, NATO offers the military and political formats and procedures to develop political guidance, and to plan and conduct military operations. It already includes key non-EU European allies (UK, Türkiye, Norway), which the EU cannot simply incorporate. It may become necessary to further informalize decision-making through NATO minus US groups. These are not alternative structures but alternating setups.
What will need to change is the direction of political initiatives. The already palpable US disinterest in NATO changes the dynamics. While in the past Washington would come up with initiatives and Europeans simply responded, the US is currently quiet. Hence, Europeans now have to adapt to this missing initial impetus. NATO military structures should be “Europeanised”: personnel the US withdraws should be replaced, and additional staff could be drawn from EU military structures and national headquarters.
If the US turns from a disinterested into a hostile actor, Europeans would have to consider either buying the US portion of NATO infrastructure and crowding out US access, or setting up alternative structures for defence planning and command.
Europeanising defence plans: Replace, re-think and integrate Ukraine
The current NATO defence plans assume that the US carry about 40% of the related military burden. Replacing US contributions seems the most straightforward way to achieve military security in the given timelines, but this requires European supply chains for forces and equipment change, as well as geo-strategic depth, if Europe alone is to ensure the continent’s defence. Moreover, personnel reserves and the availability of capabilities change. So, while replacing US capabilities, Europe also has to re-think and re-plan its future defence to be implemented at a later stage.
Replacing US capabilities involves three challenges:
1. The short-term lack of certain high-value capabilities (precision deep strike, intelligence, surveillance, reconnaissance, command & control) and the lack of multinational coordination hampers the implementation of current ways of war, such as multi-domain operations.
2. The war in Ukraine has shown that core tenets of US and NATO thinking, such as air superiority and manoeuvre warfare, are increasingly challenged. This implies that a Europeanisation may require a different approach, e.g. more static defence or more land-based strike capabilities to replace airborne strike assets, thus changing logistics, production needs, and how Europe defends itself overall.
3. Redrawing defence plans would have to anticipate the role Ukraine plays in the defence of Europe, as it can pose a significant strategic challenge to Russia, improving European options.
In pursuing their transition strategy into a European way of war, Europeans must invest in all three pillars in parallel, and fast.
Nuclear governance: Recipes for deterrence
How to ensure nuclear deterrence is both a key strategic and an intensely political question. So far, nuclear sharing ensures that NATO forces in Europe have nuclear options available, while the credible nuclear backup (second-strike capability) is delivered by the US. This was in the US interest, as it limits nuclear proliferation while also limiting the risk of a nuclear escalation. The four future options are:
1. The US continues to offer the nuclear pillar for NATO.
2. Europeans organise a form of regional nuclear deterrence, i.e. a few states carry the burden for the rest, with the authority to do so.
3. Europe focuses on conventional deterrence and counterforce, without a nuclear option beyond what France and the UK can currently provide.
4. A re-calibrated mix of nuclear and conventional deterrence offered by the US and Europe.
All options come with pros and cons. Options 1 and 4 may need to be excluded due to the severe damage that the US has done to trust in its guarantees. For any European solution, the inevitable latency in a European breakout (beyond its current nuclear powers) or significant arsenal growth (both nuclear and conventional counterforce) creates a window of opportunity for Russia. Hence, close coordination and integration with the UK and France is vital. A purely conventional counterforce approach would be exceedingly difficult to implement, as seen in South Korea.
Operational capabilities: Mass and class
NATO currently possesses approximately two thirds of the capabilities required to implement the new regional defence plans. Without the US, this share drops to about one half. The problem areas go beyond what is typically called “critical enablers”: Europe also lacks mass. Retaining the current goals of deterrence or, if that fails, stopping Russian forces early in any invasion and reversing gains requires around two corps, or about 100,000–120,000 personnel.
Regarding quality, Europeans must generate the full C4 ISTAR chain, with a focus on target acquisition. Europe does not start from scratch, though. While a full replacement will take possibly a decade, including training of personnel and developing new doctrines, some elements could be replaced within months or a few years. Commercial services may also help alleviate problems.
Industrial capabilities
Europe has the defence technological and industrial base to nurture its deterrence and defence efforts and can produce most equipment types autonomously. Replacing or finding alternative capabilities for US options is only a question of time. Europeanising and ramping up this industrial base do not mean buying only European, due to the timelines for readiness and because some products (e.g. heavy helicopters) are not available from European suppliers. For US equipment still in operation, Europe will likely continue to buy spare parts and munitions (e.g. for Patriot air defence systems) or start licenced production.
For now, Europe must prioritise effectiveness over efficiency. This means procuring on suboptimal conditions and buying on the global market where possible. Mass production and economies of scale could again be constrained by the short timelines for preparing initial capability. Skilled personnel is already a bottleneck for any scale-up effort.
European stocks and industry can still provide significant support, with stronger direct investments in Ukraine’s defence industry (the “Danish model”), which is also necessary to free up European capacity for its own rearmament efforts.
In this context, the EU has only a limited role to play: the European Commission may facilitate industrial support and support capability areas where common action is established – especially space (e.g. space-based ISR) and large-scale infrastructure projects. It might also train personnel (including offering defence awareness courses to executives, elected officials and journalists), and focus on comprehensive preparedness (e.g. coordination and regulation of civil defence).
A transatlantic transition plan
Besides the governance elements mentioned above, and a potential adaptation of defence plans, some capability areas can already be identified where procurement and build-up make sense: air defence, deep precision strike, land warfare and command and control (C2). The shift toward a more independent European way of war will be challenging and creates a window of vulnerability during the readjustment. Yet it can ultimately make Europe more secure, and there is a window of opportunity while Russia reconstitutes. This effort must be completed within 10 years, with a five-year plan for an initial capability.
Pursuing this transition strategy will require planning, deciding and investing on all pillars in parallel. Time is of the essence. Failing to agree and implement such a plan would increase the risk of another war in Europe. Europe may be vulnerable, but it has the means and the resources to manage that vulnerability.
Christian Mölling is Director of the Europe’s Future Program at Bertelsmann Stiftung
Torben Schütz is Senior Expert in the Europe’s Future Program at Bertelsmann Stiftung
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