Center for Civic Education - Lincoln Bicentennial with Supplemental Lesson: Page 8

Why did President Lincoln issue his Preliminary Emancipation Proclamation after the battle of Antietam?

One month later, on September 22, 1862, Lincoln publicly announced his “Preliminary Emancipation Proclamation.” It warned the rebels that unless they rejoined the Union by the first day of 1863, a final proclamation would be issued to free all slaves within the seceded states. Lincoln had been considering this decision for several weeks before choosing to announce it shortly after the Union army’s victory at Antietam, Maryland. He waited for a military victory in order to act from strength on this sensitive matter, which the president believed would weaken the Confederacy and thereby help “to save the Union.”

The rebels ignored Lincoln’s threat, so on January 1, 1863, he issued the Emancipation Proclamation. The president proclaimed “that all persons held as slaves” in the rebellious states “are and henceforward shall be free, and that the executive government of the United States, including the military and naval authorities thereof, will recognize and maintain the freedom of said persons.” Lincoln claimed his proclamation “to be an act of justice, warranted by the Constitution, upon military necessity.” The Emancipation Proclamation did not apply to slavery in the “border states” that remained loyal to the Union. It also exempted areas of the Confederacy already controlled by the Union.

However, after January 1, slaves were freed in the wake of Union military advances into the rebel states. Many emancipated slaves joined the Union army and navy, as authorized by the president’s proclamation. >