Institutions as Switching Circuits: Decision Synchrony under Rising Connectedness

Abstract Institutions reduce uncertainty, but by compressing decision latency and manufacturing common knowledge they can also couple decisions. We show that European systemic wars follow a behavioural mechanism: cadence converges on a shared terminal window (T_c ≈ mid-1940s), severity scales to the same T_c, and cabinet “latency ladders” (1914) reveal hours-to-days synchrony. A frozen connectedness carrier (κ) leads pre-whitened early-warning texture by ~25 years. A fixed-rule agent model - thresholds, topology, and update held constant, with only a post-event actuation ratchet (ΔJ) - suffices to generate accelerating onsets; its J read-out maps to observed severity via S\ =ρ• Population•(J_0+J), with a single historical uplift for WWII. Together these results expose an unintended war trap: rails that improve coordination also raise the probability of synchronized activation under load. We test institutional levers - safe leakage, reverse-ratchet, and decorrelation - that lengthen intervals and lower mapped severity without abandoning sovereignty.