Respuesta :
As promised, Lincoln waited to unveil the proclamation until he could do so on the heels of a successful Union military advance. On September 22, 1862, after a victory at Antietam, he publicly announced a preliminary Emancipation Proclamation, declaring all slaves free in the rebellious states as of January 1, 1863.
Lincoln realized that the Emancipation Proclamation could give him several advantages over the Confederacy in the war. First, it would give him the chance to recruit former slaves into the Union army. Lincoln also knew that once the war became an antislavery campaign, European nations would not support the Confederacy.