Tell Me What You Grow and I'll Tell You What You Think: Crop Mix and Slavery in the Us South

Abstract: Slavery had long dominated world labor relations before its demise in the nineteenth century. This paper shows that changing economic interests determined shifts in the political and ideological support for slavery within the US South. We exploit the competitive forces generated by the US Westward territorial expansion between 1810 and 1860 to identify changes in local economic incentives to the use of slave labor. We show that areas losing comparative advantage in the production of cotton with respect to wheat: (i) changed their production decisions and reduced their use of slavery, (ii) became less likely to politically defend slavery as indicated by the likelihood of legislators to vote against slavery in Congress and of counties to vote against secession, (iii) experienced changes in political outcomes as shown by electoral returns of presidential and gubernatorial candidates and roll-call behavior of Congressional representatives, and (iv) experienced a broader social transformation as shown by an increase in the free black population, and changes in local newspapers' supply of slavery-related content.