Russia’s poor military performance in the early stages of the full-scale war in Ukraine (2022-) has been attributed to various causes. This article considers possible intellectual causes of Russia’s poor performance. Reviewing public Russian military and security discussions on new wars in the years prior to Russia’s full-scale invasion, it argues that Russian operational planning on Ukraine aligned with key assumptions about new wars. In particular, the Russian leadership's failure to acknowledge Ukrainian agency, its misguided emphasis on non-kinetic means and its mistaken assumption that Western states would be unwilling to respond forcefully to Russian aggression followed key tenets of Russian new war thinking. The article raises questions about the relationship between Russian military theorizing and Russian military action, and how a prevailing intellectual paradigm shaped Russian perceptions about the reasonability of the invasion plan.