Presidents have long been seen as operating within a political environment that is intractable and highly resistant to change. Recent historical-institutional research, however, has revealed presidents to be powerful agents of structural change. Building on this emergent literature, this article endeavors to demonstrate that Terry Moe's tripartite analytical framework—of structures, incentives, and resources—remains a helpful starting point for historically oriented scholars seeking to examine the relationship between presidential behavior and institutional change. It offers methodological suggestions for conducting historical research along these lines and illustrates the potential gains by reconsidering some recent research into the relationship between presidential action and party development. Each illustration shows that presidents, through their instrumental efforts to bring inherited party structures into closer alignment with their incentives, contributed to long-term party developments. Rather than leave their structural environment undisturbed, as leading theories might predict, their actions reconfigured party arrangements and altered their trajectories, influencing the choices made by subsequent presidents and other political actors.