How does leadership turnover affect international conflict? We propose a new theory emphasizing the domestic constraints of new leaders. We argue that leadership turnover induces temporary turbulence, weakening successors who prioritize internal power consolidation before confronting external threats. Compiling a novel dataset of wars and leaders in 17 states during the Spring-Autumn and Warring States eras of ancient China, we exploit the plausible random timing of leaders’ natural deaths to identify exogenous variation in leadership turnover. We find that leadership turnovers decrease the likelihood of initiating interstate wars, while not affecting the probability of foreign attacks. We further provide supporting evidence of power consolidation. Data from 1,337 elites across 10 states during the Spring and Autumn period reveal a negative correlation between the risk of political assassination and a leader’s tenure. This paper illuminates a pivotal episode in Chinese history and suggests that domestic disruptions can unexpectedly foster international peace.