A comprehensive history of mob violence related to sectional issues in antebellum America, this book argues that the issue of slavery provoked riots in both the North and the South, the riots produced two different reactions from authorities. In the South, riots against suspected abolitionists and slave insurrectionists were widely tolerated as a means of quelling anti-slavery sentiment. In the North, both pro-slavery riots and attacking abolitionists and anti-slavery riots in support of fugitive slaves provoked reluctant but often effective riot suppression. Grimsted demonstrates that in these two distinct reactions to mob violence lay major resources of the social split that infiltrated politics and political rioting and that ultimately led to the Civil War.