Near the end of the American Civil War, the Ironclad Oath was an oath promoted by Radical Republicans that required federal employees, lawyers, and federal elected officials to swear upon entry of office that they had never supported the Confederacy. The first such law adopted by Congress was in 1862, which attempted to make the oath a requirement for the incoming members of the 38th United States Congress to take the oath. In 1863, President Abraham Lincoln proposed the Ten percent plan, which suggested that a state in rebellion could be reintegrated if a similar oath, with an additional pledge to abide by the nationwide abolition of slavery, was taken by 10% of its voters. Congress then attempted to raise this to 51% of voters in the Wade–Davis Bill of 1864, which Lincoln pocket vetoed because he thought it was too harsh. After the assassination of Lincoln in 1865, his successor, Andrew Johnson, opposed the oath altogether. Given the temporary disenfranchisement of the numerous Confederate veterans and local civic leaders, a new Republican biracial coalition came to power in the eleven Southern states during Reconstruction. Southern conservative Democrats were angered to have been disenfranchised.
