Although the direct costs of the military are well known, there is regular reference to the ‘spin-offs’ that supposedly justify military expenditure. Unfortunately, the heterogeneity and complexity of military institutions and political-economic landscapes has consistently eluded an even-keel and scientific analysis of military spinoffs. To pursue this question of military spending’s externalities further requires a stronger analytical foundation which clearly situates the military’s role within the political-economy. This work thus seeks to navigate a rich ontological landscape across a wide historical spectrum in order to colour the relationship between the military, the state, and society at large. Focusing attention on questions of military investment in human capital, military R&D, Keynesianism and other tenants of military spending, I posit that while military spending is tends to be less economically productive than comparable spending projects conducted through other means, military spending performs functions indispensable to the political-economic structure of the state.