This chapter develops the first systematic theory—the informational theory of strategic adjustment—to explain why military interventions can be crucibles of grand strategy. It argues that, by prosecuting a military intervention, states glean rich and rare information about adversaries’ capabilities and intentions, as well as their own military power and cost tolerance. The uniquely costly nature of warfighting renders this data particularly credible. Amidst background conditions of intense interstate competition and pervasive uncertainty, states face strong incentives to reassess their grand strategies in light of this new information. This process of grand strategic updating begins with a reassessment of the strategic assumptions directly tested on the battlefield, but it doesn’t end there. Indeed, the grand strategic effects of military interventions are far-reaching because information conveyed via warfighting is widely extrapolated to related strategic assessments.
Different Paths to the Modern State in Europe: The Interaction between Domestic Political Economy and Interstate Competition