The Wade-Davis Bill was a Congressional response to Lincoln's fairly lenient Ten Percent Plan. By December of 1863, the Civil War was still raging, but Union troops had already occupied virtually the entirety of Louisiana, and controlled large expanses of territory along the Mississippi. Lincoln needed to come up with a plan for readmitting conquered states, and hoped that announcing a lenient plan for readmission to the Union might sap the morale of the South. His Ten Percent Plan offered a pardon to all except Confederate military and political leaders who would take an oath of allegiance to the Union. If ten percent of people within a state were willing to do this then the state could assemble a new government and petition for admission to the Union. The only condition was that they had to accept the end of slavery.
The Wade-Davis Bill was offered by House Republicans in the winter of 1864 as a more punitive and strict alternative to the Ten Percent Plan. Its authors, Benjamin Wade and Henry Davis, demanded that fifty percent of the eligible voters from 1860 (i.e. white men) in a former Confederate state had to swear the so-called "ironclad oath" that they had never supported the Confederacy. Not only did the new state governments formed under the Wade-Davis Bill have to recognize emancipation, but they had to grant the right to vote to all black men, a very controversial proposition even in the North. These, then, were the major differences between the Wade-Davis Bill and the Ten Percent Plan. Lincoln "pocket" vetoed the Wade-Davis Bill, and the nation entered the final year of the war with no coherent plan for Reconstruction.