In this paper we present an account of practical rationality and weakness of will in terms of rational capacities. We show how our account recti'es various shortcomings in Michael Smith's related theory. In particular, our account is capable of accommodating cases of weak-willed behaviour that are not 'akratic', or otherwise contrary to the agent's better judgement. Our account differs from Smith's primarily by incorporating resolve: a third rational capacity for resolute maintenance of one's intentions. We discuss further two ways to explain the importance of resolve to practical rationality: one based on Richard Holton's recent work, and an alternative, non-consequentialist account.