This paper studies the role of leaders in the social movement against slavery that culminated in the US Civil War. Our analysis is organized around a natural experiment: leaders of the failed German revolution of 1848–1849 were expelled to the United States and became antislavery campaigners who helped mobilize Union Army volunteers. Towns where Forty-Eighters settled show two-thirds higher Union Army enlistments. Their influence worked through local newspapers and social clubs. Going beyond enlistment decisions, Forty-Eighters reduced their companies’ desertion rate during the war. In the long run, Forty-Eighter towns were more likely to form a local chapter of the NAACP. (JEL D74, J15, J45, J61, N31, N41)

Why are the east sides of formerly industrial cities more deprived? To answer this question, we use individual-level census data and create historical pollution patterns derived from the locations of 5,000 industrial chimneys and an atmospheric model. We show that this observation results from path-dependent neighborhood sorting that began during the Industrial Revolution, as prevailing winds blew pollution eastward. Past pollution explains up to 20% of observed neighborhood segregation in 2011, even though coal pollution stopped in the 1970s. We develop a quantitative model to identify the role of neighborhood effects and relocation rigidities underlying this persistence.