President Lincoln issued the Emancipation Proclamation

Lincoln announced the preliminary Emancipation Proclamation after the Union victory at Antietam in September 1862, then issued the final proclamation on January 1, 1863. It declared enslaved people in areas still rebelling against the United States to be free. The Thirteenth Amendment was not ratified until 1865, and the proclamation came after secession, not during Lincoln’s inaugural address.

AI-written and checked against the verified answer.