This paper is an investigation of the place of rhetoric in Plato's judgement that philosophers must rule. The possibility that rhetoric could facilitate the rule of philosophy raises the question of whether rhetoric could also be used to undermine the governance of philosophy. It is my thesis that Plato argues for understanding rhetoric as limited in its ability to function at cross-purposes to those of philosophy because of a basic and direct relationship between the effectiveness of rhetoric and its ability (...) to promote the ends of its audience. In the Phaedrus, we are told that persuasion requires rhetors to comprehend the nature of their audience so that appropriate methods of persuasion may be employed. This dependence on the nature of its subject is extended to include that subject's ends, an understanding of which is the province of philosophy. Since philosophy as it is put forward in the dialogues is interested in determining and promoting proper human fulfilment, then ultimately constraining the effectiveness of rhetoric in terms of the nature of its object ties rhetoric to the philosophic agenda. (shrink)