History of North America

Why did Lincoln announce his plan to free all confederate slaves soon after the Battle of Antietam?

President Lincoln did not announce a plan to free all Confederate slaves soon after the Battle of Antietam. In fact, the Emancipation Proclamation was not issued until January 1863, about five months after the battle. The Emancipation Proclamation declared freedom for all slaves in Confederate-held territory, but it did not free all slaves in the United States. It was a preliminary step to the ratification of the Thirteenth Amendment, which officially outlawed slavery in the United States in December 1865.