This dissertation advances a new framework for examining internal divisions on the northern home front during the American Civil War. Most previous studies focus on whether political opposition, specifically Peace Democrats or “Copperheads,” imperiled the Union. This project argues that popular fears and perceptions about wartime dissent proved as important in shaping the home front as actual opposition. I maintain that the dominant political culture in the North exaggerated the threat of a dangerous fifthcolumn. Newspapers and other print sources reacted to real acts of dissent with hysteria and violent rhetoric, including the encouragement of extralegal activity to suppress “disloyal” behavior. Five thematic Chapters demonstrate how citizens and government officials perceived internal dissent as something more treacherous and widespread than it actually was, and reacted with violent counter measures. Topics include pro-Union mobs destroying antiwar newspapers; how fears about secret societies and conspiracies to resist the draft precipitated riots; the way intimidation and military interference influenced northern elections; and finally, how the North erupted in mob violence after Abraham Lincoln’s assassination.

These moments of conflict hold a larger significance that challenges conventional interpretations about the northern home front. Diaries and private letters provide strong evidence that the threat of violence influenced some citizens to keep opposing views silent, and compelled others to express patriotic affirmations in public. As such, a major theme of this project is that moments that appear to symbolize widespread consensus, such as the lack of dissenting voices early in the war, widespread celebrations and mourning in 1865, and Republican victories in important elections, reflected a fragile unity in the Civil War North where intimidation and violence from pro-war citizens masked deeper internal divisions.