The Ironclad Oath was an oath promoted by Radical Republicans and opposed by President Abraham Lincoln during the American Civil War. The Republicans intended to prevent political activity of ex-Confederate soldiers and supporters by requiring all voters and officials to swear they had never supported the Confederacy. Lincoln's reconstructive policy toward the South was lenient because he wanted to popularize his Emancipation Proclamation. Lincoln feared that compelling enforcement of the proclamation could lead to the defeat of the Republican Party in the election.
