This article looks at the causes of rural conflict in 1930s Spain. Rather than stressing bottom-up forces of mobilization linked to poor harvests and rural unemployment or the inability of the state to enforce reformist legislation, this article explores the role of state policy in sorting out the acute coordination and collective action problems of mobilizing rural labourers. This is done by looking at the effects of intervention on rural labour markets in dry-farming areas of Spain (parts of Castile and of Andalusia). Given the difficulties of constructing a conclusive test of the hypothesis, three indirect testing strategies are used. The first is an examination of the qualitative evidence on the functioning of labour markets in dry-farming areas of Spain. Second, because the argument presented in this article implies the existence of severe restrictions on the labour supply of rural labourers during the harvest in the early 1930s, harvest-to-winter wage ratios before and after the passing of legislation are studied. Finally, the diffusion of union offices and general strikes in several dry-farming provinces of Spain is examined, in order to show that alternative hypotheses to explain rural conflict are not consistent with the historical record.