In December 1863 Lincoln introduced the first Reconstruction scheme, the Ten Percent Plan, thus beginning the period known as Presidential Reconstruction. The plan decreed that when one-tenth of a state's prewar voters had taken an oath of loyalty to the U.S. Constitution, its citizens could elect a new state government and apply for readmission to the Union. In addition, Lincoln promised to pardon all but a few high-ranking Confederates if they would take this oath and accept abolition. The plan also required that states amend their constitutions to abolish slavery. Conspicuous in this plan was the stipulation that only whites could vote or hold office.