Typically, neoclassical realist scholars who prioritise state capacity as an intervening variable in their studies have often implied that states directly convert increased state capacity into improved military capabilities, leading them to engage in internal balancing and, occasionally, war. This article argues that the causal chain from state capacity to military modernisation and balancing is not as straightforward as the existing literature makes it look like. Using Russia’s 2022 invasion of Ukraine as a plausibility-probe study, we propose that before states move from underbalancing to balancing, the process by which state capacity is translated into improved military capabilities might depend on conditional mechanisms. This novel theoretical model is labeled ‘conditional state capacity neoclassical realism’ and provides more case-specific explanatory power than the old state capacity theory.