This article examines and assesses virtues and limits of the contribution of political constitutionalism to the question of reasoning about rights. In the first section, the role of legislatures in deciding about rights is examined and compared to judicial reasoning. The main tenets of the parliamentary style of politics are sketched out. The second section tries to establish that weak judicial review of legislation is compatible with political constitutionalism, but it shows also that some forms of strong judicial review may be necessary in certain cases. In order to prove this latter point, the third section takes the Hirst case as its focus. From an analysis of the parliamentary debate on the issue of prisoners’ right to vote, it is noted that the political process is not always the best institution for adjudicating questions that concern directly the political process itself and that are constitutive of the whole political system. The last section pushes this point a little further by showing that the pre-conditions of the political constitution are rarely taken into account by political constitutionalists. In this respect, constitutional rights that form constitutive aspects of the political process may deserve a stronger protection than other rights and in this respect judicial review might play an important role.