Liberal rights theory can be used either to challenge or to support social hierarchies of power. Focusing on Ronald Dworkin's theory of rights and Catharine MacKinnon's feminist critique of liberalism, I identify a number of problems with the way that liberal theorists conceptualize rights. I argue that rights can be used to chal-lenge oppressive practices and structures only if they are defined and employed with an awareness and critique of social relations of power.