During the American Civil War, the Mennonites and Amish faced moral dilemmas that tested the very core of their faith. How could they oppose both slavery and the war to end it? How could they remain outside the conflict without entering the American mainstream to secure legal conscientious objector status? In the North, living this ethical paradox marked them as ambivalent participants to the Union cause; in the South, it marked them as clear traitors.

In the first scholarly treatment of pacifism during the Civil War, two experts in Anabaptist studies explore the important role of...