There is growing concern among democracy scholars that participatory innovations pose a depoliticizing threat to democracy. This article tackles this concern by providing a more nuanced understanding of how politicization and depoliticization take shape in participatory initiatives. Based on ethnographic research on participatory projects with marginalized people who are invited to act as experiential experts, the article examines how actors limit and open up possibilities to participate. By focusing on struggles concerning the definition of expertise, the article identifies a threefold character of politicization as a practice within participatory innovations. It involves (1) illuminating the boundaries that define the actors’ possibilities; (2) making a connection between these boundaries and specific value bases; and (3) imagining an alternative normative basis for participation.