The defence spending of EU member states has increased substantially since Russia’s full-scale invasion of Ukraine. Kamil Zwolski argues this extra spending must now be accompanied by a coherent long-term security strategy.

The full-scale invasion of Ukraine in 2022 fundamentally destroyed Europe’s post-Cold War security assumptions, especially among those states that did not draw the correct conclusions in 2014, following Russia’s first invasion of Ukraine.

Three years into the conflict, Europe faces a paradox. On the one hand, Europe unequivocally committed to helping Ukraine defend itself and embraced Ukraine as a future EU member. On the other hand, Europe’s reactive approach and the half-hearted commitment of countries like Germany risk perpetuating a cycle of escalation without a credible vision of the settlement.

Notably, defence spending across EU member states has increased by over 30% since 2021 and initiatives such as the €800 billion ReArm Europe Plan convey the message that the continent is now serious about deterrence and that urgent measures are being adopted at both the EU and national levels.

The problem for the EU, however, is the same as it has ever been: ambitious financial commitments cannot substitute for strategic clarity. Europe’s credibility as a security actor depends not only on the size of its armies but also on being able to move beyond the crisis-driven response and formulate a coherent long-term strategy that balances military resilience with pragmatic diplomacy. Developing a strategy, however, is easier said than done, considering the hard choices that lie ahead.

The limits of Europe’s reactive approach

The war in Ukraine exposed Europe as overly relying on NATO (the US), as well as being fragmented in terms of national defence policies. NATO did indeed reaffirm its role as the cornerstone of collective defence in the transatlantic area, but the problems for Europe are hard to ignore.

First, there is the dependency on US leadership. European NATO members’ combined defence spending reached €326 billion in 2024, but only 50% of German military assets were combat-ready, with Germany’s combat readiness actually lower in 2024 than it was in 2022. Without US military, intelligence and logistical support, Europe’s ability to project power remains severely constrained – a vulnerability further highlighted by the fact that if an EU member state is attacked, it could take 45 days for “other members to get permission to move equipment across borders in response”.

Second, there is energy dependence. As recently as 2021, the EU’s dependency on Russian natural gas stood at 45%, effectively inviting Moscow to weaponise its energy market. President Trump criticised German extensive reliance on Russian natural gas at the 2018 UN General Assembly meeting, dramatically noting that “Germany will become totally dependent on Russian energy if it does not immediately change course”. This statement famously drew laughter and smirks from the German delegation and other diplomats in the room.

Third, there is institutional fragmentation. The EU’s 2022 Strategic Compass called for a “Rapid Deployment Capacity” of 5,000 troops, but this and other commitments is undermined by the overall lack of sufficient cohesion between EU member states, as exemplified by Hungary and Slovakia’s pro-Russia stance.

In short, sanctions, military assistance and policy documents have become substitutes for the actual medium-to-long term strategy. Russia’s economy, though affected by sanctions, has adapted through partnerships with Iran and China, while its military is rebuilding its forces faster than anticipated.

Lessons from the Ukraine war

The war’s early phases provided some successes but also exposed sobering realities. One of the key lessons was that military readiness matters. Finland’s conscription model is widely recognised as a major source of military resilience, with a small peacetime force but a vast, well-trained reserve that can be rapidly mobilised. This stands in contrast to Germany’s professional army, which has struggled with readiness and lacks a comparable reserve base.

The war has also demonstrated that unity has limits. EU sanctions require unanimity, but exceptions were made for several countries. For example, after Russia’s invasion of Ukraine, Hungary negotiated an exemption from the EU’s oil embargo, allowing it to continue importing Russian oil. Slovakia and the Czech Republic were also included in the exemption.

Finally, it has shown that hybrid warfare is the new norm. Russian cyberattacks on German infrastructure and disinformation campaigns targeting French elections require integrated responses beyond traditional defence. Crucially, the conflict has exposed Europe’s failure to anticipate Russia’s willingness to absorb massive losses for geopolitical aims.

Strategic pathways for a post-war Europe

Europe faces three viable but imperfect options. The first option is doubling down on deterrence. On the plus side, this would align with NATO’s reinforced eastern flank approach and would also leverage the US nuclear umbrella. However, in the medium term, it would perpetuate European dependency on American commitment and ignore opportunities for diplomatic off-ramps. The ReArm Europe programme could minimise capability gaps, but it risks furthering arms-race dynamics.

A second option is to pursue strategic autonomy. There are positive signs for this approach, as both the EU’s Permanent Structured Cooperation (PESCO) and the European Defence Fund promise deeper integration. France and Germany’s push for an EU nuclear deterrent also suggests ambition. Yet there are also divergent threat perceptions that could undermine consensus (for example, Poland’s focus on Russia compared with Spain’s Mediterranean concerns). A recent report by the European Court of Auditors warns that moving tanks across borders still takes weeks.

The final option is selective engagement. This could build on the principles of the EU’s 2016 Global Strategy and incorporate “pragmatic cooperation” on issues of shared interest, like Arctic governance. It could also involve leveraging discontent among Russian oligarchs to undermine Putin’s regime. On the downside, such a strategy would risk legitimising aggression and lacks public support in several central and eastern European countries.

Toward a hybrid strategy – deterrence with diplomacy

A more sustainable future approach will require combining military credibility with tools of diplomacy. First, there is a need to credibly define red lines. Europe, including the UK and the EU, must clarify responses to a range of scenarios, including nuclear threats, continuous hybrid attacks against European institutions and the possibility of a Russian military breakthrough in Ukraine. The EU’s planning must incorporate the use of its Rapid Deployment Capacity.

Second, the EU should strive to compartmentalise cooperation. After the Ukraine war ends, the EU should engage Russia, if and when possible, on issues such as cybersecurity governance and climate-driven Arctic security, while also maintaining its “Ukraine First” policy.

Third, the EU must define and defend what Sven Biscop calls the “zone of responsibility”, namely “a geographic area around the EU that must remain stable for the EU itself to enjoy stability”. The EU must decide what relationship it wants to offer to the countries within that zone and how it is going to defend it. The 2023 EU-NATO Joint Declaration calls the relationship “complementary, coherent and mutually reinforcing”, but Europe must lead rather than follow.

Policy priorities for European leaders

This leaves four key policy priorities for European leaders. The first is to accelerate defence integration by merging national procurement via the European Defence Fund and prioritising drone and AI technologies. In its latest funding round, the European Defence Fund allocated €910 million to 62 projects, focusing on drones, autonomous mine-sweeping, AI-driven defence systems and counter-hypersonic technologies.

The second priority is to adopt qualified majority voting (QMV) on sanctions, thereby overriding veto powers that enable Russian leverage. Currently, EU sanctions require unanimity, allowing any member state to block or dilute measures. The EU treaties already allow for QMV in certain foreign policy areas, and there is growing pressure from the European Commission, Parliament and some member states to expand its use to sanctions.

The third priority is to launch a “Security Cohesion Fund” that can redirect a portion of cohesion policy budgets to secure energy grids and cyber defences in frontline states. The European Commission has already identified defence as a new priority for cohesion policy, allowing member states to use these funds for infrastructure, dual-use goods and security upgrades.

The final priority is to establish an EU-Russia crisis hotline following the end of the Ukraine war. This would mirror the Cold War-era US-Soviet hotline, which was established to prevent misunderstandings and accidental escalation, providing a direct communications link between leaders.

Note: This article gives the views of the author, not the position of EUROPP – European Politics and Policy or the London School of Economics. Featured image credit: European Union