Thirteenth Amendment to the United States Constitution

After implementing the Emancipation Proclamation, Lincoln increased pressure on Congress to outlaw slavery throughout the nation with a constitutional amendment. He declared that such an amendment would "clinch the whole matter" and by December 1863 an amendment was brought to Congress. This first attempt fell short of the required two-thirds majority in the House of Representatives. Passage became part of the Republican/Unionist platform, and after a House debate the second attempt passed on January 31, 1865. With ratification, it became the Thirteenth Amendment to the United States Constitution on December 6, 1865.