HHow does leadership turnover affect international conflict? We propose a new theory emphasizing the domestic constraints of new leaders. Leadership turnover results in successors who, regardless of their absolute strength, initially face a period of relative political vulnerability. We argue that new leaders prioritize consolidating power—through repression, co-optation, and reforms—before engaging in external conflict. Using a novel dataset of wars and rulers in 17 states during the Spring-Autumn and Warring States eras (771–221 BCE) of ancient China, we leverage exogenous variation in leadership turnover induced by rulers' natural deaths. We find that leadership turnover decreases the likelihood of initiating interstate wars. To further substantiate our theory, we present both empirical and anecdotal evidence of power consolidation strategies during leaders' early tenure. Our findings contribute to debates on the diversionary use of force and the broader role of domestic politics in shaping international conflict.