Comparative constitutional law studies on who has the last word in a democratic system have focused on models of ex post control of the constitutionality of laws. However, models of constitutional justice incorporate some forms of prior review of constitutionality. This article focuses on those cases in which judges speak first. For that reason, it refers to the problems and challenges that prior review of constitutionality represents for democracy. Specifically, those challenges related to exercise it and to act dialogically with the other branches of government. In particular, the issues related to the need to imagine the problems of constitutionality, the lack of citizen participation and the inevitable rupture of res judicata are addressed. All this is studied within the contextual framework of one of the most active and sophisticated prior judicial review systems in the world, as it’s the case for the Colombian system.