KSE Institute has published a new study, Rethinking European Security in the Face of the Russian Threat. The authors examine how Russia’s aggression and the US’s pullback have exacerbated vulnerabilities in Europe’s security architecture, and how wartime lessons from Ukraine—and Ukraine itself—can be integrated into Europe’s defense.

Europe confronts the return of war. After decades of underinvestment in defense, Europe has been jolted awake by Russia’s full-scale invasion of Ukraine. Moreover, Moscow’s buildup of long-range and nuclear-capable weapons, along with its covert operations and strategic partnerships with Iran, North Korea, and China signals preparations for potential conflicts beyond Ukraine. With future US commitments to European security uncertain at best, Europe is boosting defense spending and loosening fiscal rules, but it must also reform procurement and rebuild its defense-industrial base. Despite having far greater economic power than Russia, Europe must also spend more effectively. Ukraine’s wartime experience offers valuable lessons and should be integrated into European defense planning.

Strategic lessons from Ukraine’s defense against Russian aggression include:

• Information superiority: Battlefield success depends as much on data as on munitions; an advanced situational awareness system like Ukraine’s DELTA, integrated with AI, is indispensable, and sovereign space assets and connectivity alternatives should be prioritized.

• Battlefield testing: Weapons and systems must be rapidly adapted through combat-driven feedback and field innovation.

• Cost asymmetries: Means of destruction are becoming cheaper while countermeasures remain expensive; interceptor drones and FPV-drone resilience can help make deterrence more cost-effective.

• Innovation vs. conventional capabilities: New technologies must complement, not replace, conventional systems; armored vehicles and high-speed ballistic missiles remain essential alongside drones.

• Defense ecosystem: Private entrants need easier market access and targeted support; defense tech clusters like Ukraine’s Brave1 and agile procurement strengthen defense-industrial resilience. 

• Battlefield dynamics: Russia’s reliance on artillery and expendable mass—drones, manpower, and materiel—demands scalable European countermeasures.

• Industry and technology: Russia’s centralized military-industrial complex enables rapid scaling at the cost of flexibility and relies on Western-made components; Europe must accelerate SME-led innovation and scale production with the help of large incumbents.

• Global dependencies: Rosatom and Roscosmos support Russia’s missile, nuclear, and space capabilities under civilian pretenses—scientific and commercial ties should stop; Europe must promote competitive arms exports to weaken Moscow’s military revenue and influence.

Next steps: rearming Europe and integrating Ukraine. Europe is rearming at scale, but without structural reform, its rising defense budgets risk reinforcing dysfunction rather than building deterrence. Ad hoc tools like SAFE and EDIRPA cannot overcome entrenched fragmentation. A centralized mechanism can align spending with strategy, but it will require real political will. Ukraine and its experience, meanwhile, have become crucial to Europe’s security: battlefield innovations, industrial scale-up, and rapid procurement under fire offer the most relevant lessons for modern defense. Excluding Ukraine from Europe’s defense architecture would not just be a missed opportunity, but could turn into a strategic failure.

Policy recommendations. In order to establish effective deterrence against Russia, Ukraine should be integrated into the European security architecture. This should entail inviting it into European defense bodies and planning, including it in defense industrial strategy, and incorporating its field experience into training and doctrine. In addition, joint defense production should be advanced, including by involving Ukraine in PESCO, joint projects and procurement, and co-production. It is also critical to boost capacities and innovation by expanding the role of the European Defense Agency, cultivating joint innovation ecosystems, and leveraging civilian tech and agile R&D. Finally, the exchange of knowledge and best practices should be facilitated through a permanent European-Ukrainian lessons-learned mechanism, the sharing of cross-society and civil-military practices, the transfer of field-proven technologies, and a broader exchange of training and command.