The most destructive urban violence in U.S. history occurred in New York City during four days of draft riots, July 13 to July 16, 1863. In the midst of the Civil War, tens of thousands of mainly foreign-born (mostly Irish) workers poured onto the streets to protest the new draft law that made them, not the wealthy, likely to be conscripted into the army. Rioters attacked the city's draft headquarters, defied police, looted stores, and sought out African-American victims to hang from the lampposts. During those four days, New York City became a battlefield.

In general, most wage workers in the North supported the Union and Abraham Lincoln's policies in the war. However, they were increasingly disturbed by what they considered to be inequities in the conscription, or draft, laws. They were especially antagonized by a new draft provision that allowed anyone...