This paper examines how the encounter of radical activism and peasant militancy reshaped economic and political relations—indeed, the forms and functions of informal and state institutions—in northwestern Pakistan. The 1970s Frontier peasant movement achieved lasting de facto land and tenancy reforms that were ultimately regularized by state intervention. I argue that both the de facto land reforms and the state intervention itself were consequences of the rising organizational (and armed) power of tenants and landless labourers under the radical Mazdoor Kisan Party. In making this argument, I also enquire into the place of class analysis in the study of radical politics and state formation in South Asia.