Are leaders more likely to face militarized challenges earlier in their tenure? Existing studies posit contradictory hypotheses: new leaders can both invite challengers to take advantage of their inexperience and deter challengers by their strong incentive to establish a reputation for resolve. This paper seeks to reconcile these competing propositions by developing an argument that centers on the direction of foreign policy preference change associated with leadership turnover. I argue that foreign adversaries are likely to challenge a new leader in their rival state only when the newcomer is perceived to be more hawkish than the predecessor. The perception of a heightened risk of conflict accompanied with the emergence of a more hawkish leader in the rival state gives foreign adversaries a stronger incentive to seek for an early confrontation in which they can (re)demonstrate their own position to the new hawk. In contrast, when the newcomer is perceived to be more dovish than the predecessor, optimistic expectations of future interactions tend to restrain foreign adversaries from provoking the new dove, whose reputation concerns are high. A series of statistical analyses on post-WWII dyadic rivalries with democratically elected leaders on the target side yield strong evidence that supports this conditional hypothesis.