Habermas dialogically recasts the Kantian conception of moral autonomy. In a legal-political context, his dialogical approach has the potential to redress certain troubling features of liberal and communitarian approaches to democratic politics. Liberal approaches attach greater normative weight to negatively construed individual freedoms, which they seek to protect against the interventions of political authority. Communitarian approaches prioritize the positively construed freedoms of communal political participation, viewing legal-political institutions as a means for collective ethical self-realization. Habermas’ discourse theory of law and democracy seeks to overcome this competition between the negative and positive liberties. Doing so entails reconciling private and public autonomy at a fundamental conceptual level. This is his co-originality thesis, which seeks to show that private and public autonomy are internally connected and evenly balanced. I support his aim but argue that he fails to achieve it due to an unsatisfactory account of private autonomy. I suggest an alternative dialogical conception of autonomy as ethically self-determining agency that would enable him to establish his thesis.