Written by Margaryta Khvostova. Rita is a PhD student at the Politics & International Relations department, University of Surrey, specialising in security, hybrid warfare and human rights.
Four years ago, Russia’s full-scale war against Ukraine shattered the post-Cold War European security order – and in doing so, put Europe under the most severe stress test of its economic assumptions, institutional architecture, and political will. Stress tests only matter if the results are acted on. Today, the picture is mixed in ways that should prompt serious reflection in European capitals: the vulnerabilities closest to the surface have been managed reasonably well, but the deeper you look, the less convincing the adaptation becomes.
Energy: the false hope of interdependency
Europe’s dependence on Russian energy was not a discovery made in February 2022. What the invasion exposed was not the dependency itself but the assumption underneath it: that economic interdependence was a form of deterrence. It was not.
However, what followed was more successful than most predicted. Europe diversified its gas supply, fast-tracked LNG infrastructure, and cut Russian energy imports dramatically – all without the economic catastrophe that many had feared. This is the stress test working as intended: pressure producing adaptation.
But the adaptation has not been universal. Hungary and Slovakia retained Russian energy supplies and have since used that continued dependency as leverage inside EU decision-making, blocking or diluting measures on Ukraine not so much out of strategic principle, but as a tool for political bargaining. The problem is no longer Moscow weaponising European energy dependency. It is EU member states doing so themselves. That is a more corrosive vulnerability, because it sits inside the institutions rather than outside them.
Unity: together when it counts, divided when it matters
On the surface, European unity has been remarkable. Ukraine received EU candidate status, sustained financial support, and military assistance that have been pivotal in allowing the country to hold its ground against one of the world’s largest military powers.
But crisis-driven unity is not structural unity. The same dynamic that played out in the energy debate – member states exploiting unanimity requirements for political leverage – has repeatedly delayed EU support measures. The consequence has been significant: the most effective support mechanisms have emerged outside the EU’s formal structures. The Ukraine Defence Contact Group and the Coalition of the Willing have been more agile because they do not require everyone to agree. The Czech-led ammunition initiative, which sourced artillery shells from outside the EU when European production could not keep pace, is the clearest example – a workaround that worked but should not have been necessary.
The underlying problem remains unsolved, and it will matter for what comes next. Ukraine’s EU accession process requires consensus at every significant stage. Europe does not yet have a convincing answer to how it manages member states prepared to use their veto for short-term political gain throughout that process.
Defence: strong rhetoric without depth
The war has exposed the distance between Europe’s deterrence posture and its actual industrial capacity to sustain it. Ammunition shortages emerged quickly. Production ramp-ups have been slow. Procurement remains fragmented across dozens of national systems that do not interoperate – a problem that was simply possible to ignore when a land war in Europe seemed implausible.
The shift in Washington has sharpened the stakes. If Russia were to test the eastern flank, Europe would need to respond with sufficient speed and firepower, potentially without full American involvement. Whether it is currently capable of doing so is genuinely uncertain. Increased defence budgets are necessary but not sufficient – capability requires coordination, and Europe is building it slowly from a low base.
What is less often discussed is the most underutilised asset available: Ukraine itself. Ukrainian forces have spent four years solving, under combat conditions, exactly the interoperability problems that European planners are now grappling with in theory. Incorporating Ukraine as a meaningful participant, rather than just a beneficiary, into European military frameworks would be both practically valuable and strategically overdue. Expanded military co-production is the obvious place to begin – it serves both sides, and investing in Ukraine’s defence industry now costs Europe far less than filling the capability gap alone.
Hybrid warfare: the front already open
While Europe works to close these conventional gaps, a different kind of attack is already underway. Much of the European debate has focused on whether Russia might one day attack NATO territory. But Russia’s hybrid campaign against Europe is not a future scenario – it is an ongoing confrontation. The challenge is this: hybrid warfare is multi-domain by design, combining disinformation, cyberattack, infrastructure sabotage, and political interference in mutually reinforcing ways, while Europe’s response mechanisms remain largely single-domain and nationally siloed. Russia understands this gap and has calibrated its campaign to exploit it.
The evidence is not hard to find. Russian-linked operations have targeted elections across the continent through coordinated disinformation, hit critical infrastructure through cyberattacks, weaponised migration on the Finnish and Polish borders, and severed undersea cables in the Baltic under circumstances pointing toward deliberate sabotage.
For the UK, the undersea infrastructure dimension is particularly acute, as cables and pipelines are difficult to protect and the threshold for attribution and response remains deliberately ambiguous, making them attractive targets. A coordinated UK-European strategy to address this does not yet exist.
Hybrid attacks are not a stable equilibrium. They are a probing strategy: if met with managed adaptation rather than credible deterrence, they create conditions for escalation. A conventional attack on NATO territory remains high-risk for Russia. Hybrid pressure that erodes European cohesion and democratic resilience is low-cost, cumulative, and unlikely to decrease in intensity.
The lesson Europe has not yet fully learned
Ukraine learned about Russia’s escalation logic the hard way – through the years between 2014 and 2022, when pressure below the threshold was met with responses calibrated to de-escalation rather than deterrence. When the full-scale invasion came, it came in part because insufficient resistance had been signalled over eight years.
Four years on, Europe has demonstrated real capacity for crisis-driven mobilisation. What it has not demonstrated is the structural reform in its institutions, its defence-industrial base, and its hybrid response architecture that would make deterrence credible rather than assumed. Russia has spent four years learning from this war too, recalibrating its tactics and continuing to probe where resistance is weakest. The stress test is not over. The question is whether Europe is treating it as an ongoing challenge to be met, or a crisis that has been weathered and can now be managed down.
This may sound pessimistic, and on the evidence alone, it risks missing something important. Ukraine still holds. Despite everything Russia has thrown at it, Ukrainian society has not broken, its military has not collapsed, and its determination to fight for its own future has not wavered. European and British support, far from fading, has grown. There is a real story of resilience here.
But anniversaries like this one are not really occasions for optimism or pessimism. They are occasions to pay respect to those who are fighting for a European future they may never fully enjoy, to look honestly at the mistakes that have been made, and to commit to not wasting the lesson. Ukraine is paying an enormous price to ensure that Europe’s exposed vulnerabilities do not become Europe’s undoing. Can Europe seize the opportunity to learn and reform?
