The process of reconstructing the Union began in 1863, two years before the Confederacy formally surrendered. After major Union victories at Gettysburg and Vicksburg, Abraham Lincoln issued the Proclamation of Amnesty and Reconstruction in which he outlined his Ten-Percent Plan. The plan stipulated that each secessionist state had to redraft its constitution and could reenter the Union only after 10 percent of its eligible voters pledged an oath of allegiance to the United States.