How does a movement for social justice, whose members are mainly drawn from the lower economic strata of society, build and sustain its power in the face of co-option, and social and geographical division? Members of the Bunge La Mwananchi movement in Kenya explored this question using action research. The movement carves spaces for debate and activism in the urban public sphere accessible to the unrepresented masses. The authorities leave these spaces mostly unmolested, in part because co-option by politicians and civil society organisations is as effective at wrong-footing the movement as mass arrests and riot police would be. The research reminded the members that the movement's power has always lain in its efforts to reach across internal divisions of ethnicity, gender, class and geography. As the research connected the debaters in one site with those in another, it demonstrated how communicative enquiry works to create solidarity within this most grass-roots of movements.