Was the Russian Invasion of Ukraine a Failure of Western Deterrence? by Bettina Renz In February 2022, many observers initially evaluated the Russian invasion of Ukraine as a failure of Western deterrence. That assessment was and is flawed inasmuch as the West never articulated a clear strategy to deter such an invasion. Engaging with relevant conceptual debates about how deterrence works and relating this information to what the West did and did not do in the run-up to the invasion, this article shows that deterrence efforts were based on problematic assumptions about the Kremlin’s motivations. The study concludes with lessons for Western military and policy practitioners with the intention to enable better future thinking about how to deter Russia.