American Mobbing, 1828-1861 is a comprehensive history of mob violence in antebellum America. David Grimsted argues that, though the issue of slavery provoked riots in both the North and the South, the riots produced two different reactions. In the South anti-slavery rioting was widely tolerated and effectively encouraged Southern support for slavery. In the North, both pro-slavery and anti-slavery riots were put down, often violently, by the authorities, resulting usually in a public reaction against slavery. Grimsted thus demonstrates that mob violence was a major cause of the social split that led to the Civil War.