Although they remained loyal to the Union, political parties fractured in the North during the Civil War. Northern Democrats who opposed the war and demanded an immediate peace settlement with the South labeled themselves “Peace Democrats;” Republicans called them “Copperheads.” Their opponents accused the Peace Democrats of disloyalty and suspected them of aiding the Confederates. As result, a Union general in Ohio issued General Order No. 38, making "the habit of declaring sympathies for the enemy" illegal in the state. After Congressman Clement Vallandigham, a vocal Peace Democrat, was arrested, some accused Lincoln of violating constitutional liberties and demanded that Vallandigham be released. Lincoln commuted Vallandigham's sentence from imprisonment to banishment behind Confederate lines.
The Hon. Clement Laird Vallandigham, ca. 1855–1865. Prints and Photographs Division, Library of Congress.