For decades, the central question of Ukraine’s relationship with Europe was whether Ukraine would ever become part of the European Union. Today, the debate has fundamentally changed, and the question is no longer whether Ukraine belongs to Europe, but rather if Europe can credibly defend itself in today’s volatile security environment without Ukraine.

The answer is clear: it cannot.

Ukraine is steadily becoming one of the key security providers on the European continent. This had stemmed not simply from its ability to withstand the largest war in Europe since 1945, but from the fact that in this time, Ukraine has developed the continent’s most combat-experienced military, one of the world’s most innovative defense tech sectors, and a new doctrine of warfare that is changing how the world is going to fight wars in the future.

From battlefield drones and artificial intelligence-enabled targeting to rapid innovation cycles between the front-line units and manufacturers, Ukraine is pioneering capabilities many NATO and EU states are only beginning to comprehend.

The war has transformed Ukraine from a consumer of European security to a net provider of it.

Discussions in Brussels increasingly focus on how Ukraine can be integrated into Europe’s political and security structures before the full EU membership is completed.

One proposal put forward by German Chancellor Friedrich Merz is a phased integration that would allow Ukraine to participate in key EU meetings and instruments prior to its formal accession.

While Kyiv has, perhaps understandably, been cautious about what could constitute any substitution for the full membership, many European policymakers view such measures not as an alternative to accession but as a viable mechanism to accelerate. Unconventional times call for unconventional means.

The reality is that Europe faces its own political constraints.

Upcoming elections across several member states, as well as the eventual need for national referendums and ratification procedures, create uncertainty about the accession timeline.

Concurrently, the security challenges are not waiting for the European bureaucracy to catch up. As a result, Europe is considering how to begin the practical integration sooner.

Ukraine has aligned its foreign and security policies with the European Union to an unprecedented degree, thus almost fulfilling Cluster Six — External Relations. It is increasingly connected to European defense-industrial initiatives and is becoming an integral component of Europe’s broader defense ecosystem.

The logical next step is deeper participation in the institutions that form European security policy and defense cooperation.

In a recent research paper for the Wilfried Martens Center for European Studies, I argued that Europe is entering a period of strategic transition in which existing security structures will need to evolve to meet the challenges of our time — aggressive Russia, growing instability around Europe, and an increasing uncertainty about America’s engagement on the continent.