Since the American Revolution, states had divided into states that allowed or states that prohibited slavery. Slavery was implicitly permitted in the original Constitution through provisions such as Article I, Section 2, Clause 3, commonly known as the Three-Fifths Compromise, which detailed how each slave state's enslaved population would be factored into its total population count for the purposes of apportioning seats in the United States House of Representatives and direct taxes among the states. Though many slaves had been declared free by President Abraham Lincoln's 1863 Emancipation Proclamation, their post-war status was uncertain. On April 8, 1864, the Senate passed an amendment to abolish slavery. After one unsuccessful vote and extensive legislative maneuvering by the Lincoln administration, the House followed suit on January 31, 1865. The measure was swiftly ratified by nearly all Northern states, along with a sufficient number of border states up to the death of Lincoln, but approval came with President Andrew Johnson, who encouraged the "reconstructed" Southern states of Alabama, North Carolina and Georgia to agree, which brought the count to 27 states, and caused it to be adopted before the end of 1865.
Though the amendment formally abolished slavery throughout the United States, factors such as Black Codes, white supremacist violence, and selective enforcement of statutes continued to subject some black Americans to involuntary labor, particularly in the South. In contrast to the other Reconstruction Amendments, the Thirteenth Amendment was rarely cited in later case law, but has been used to strike down peonage and some race-based discrimination as "badges and incidents of slavery." The Thirteenth Amendment applies to the actions of private citizens, while the Fourteenth and Fifteenth Amendments apply only to state actors. The Thirteenth Amendment also enables Congress to pass laws against sex trafficking and other modern forms of slavery.
Section 1. Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
Section 2. Congress shall have power to enforce this article by appropriate legislation.