Historical Grand Strategy as Selective Causal Modeling: Civil–Military Coupling, Causal Legibility, and the Limits of Playable History

Historical grand strategy games cannot model every aspect of the past. They must decide which relationships to represent in detail and which to simplify. This article examines the consequences of those choices through Hearts of Iron IV (with version 1.19.2), focusing on the limited connections between its civilian economy and military systems. A close analysis of the game's mechanics, compared with scholarship on wartime mobilization, shows a clear asymmetry: military production is represented in considerable detail, while the civilian economy is compressed into a much smaller set of aggregate variables. This matters not simply because the game is an imperfect representation of history. It shapes the kind of history that becomes visible in play. Wartime mobilization is presented primarily as the conversion of civilian resources into military power, while many of the social costs, institutional constraints, and feedback effects of that conversion remain less visible. In turn, these design choices influence which counterfactual questions players can readily explore and, particularly for players with limited prior knowledge, might influence their expectations about how wartime economies worked. The article concludes by considering the broader trade offs faced by historical simulations between causal adequacy, cognitive tractability, strategic choices, and commercial accessibility, with ethical representation treated as a further constraint.