This chapter reclaims cosmopolitanism’s radical potential and proposes the migrant as the key figure in a cosmopolitan practice that promises to ground cosmopolitanism from below. Migrant voices and acts of citizenship help us overcome the cognitive bias of methodological nationalism and ground a robust, feasible cosmopolitanism. Although there is a constant danger that migrant protests may become assimilated to nationalist narratives, migrant protest movements are the most overt manifestations of a cosmopolitanism from below. The act of migrating, whatever the intention, is a de facto cosmopolitan act, causing a ripple or a rupture in the national fabric, the illegalized migrant who crosses national frontiers being the cosmopolitan actor par excellence in rejecting coercively imposed national borders.