What role did the Battle of Antietam play in the Emancipation Proclaimation?

The Battle of Antietam, fought on September 17, 1862, was the bloodiest single-day battle in American history and a strategic Union victory. This win provided President Abraham Lincoln with the political capital he needed to issue the Emancipation Proclamation. Announced shortly after the battle, the proclamation declared the freedom of enslaved people in Confederate-held territory, transforming the Civil War from a fight for the Union into a battle against slavery and allowing the Union to enlist Black soldiers.