How did the Thirteenth Amendment end slavery in the United States?

The Thirteenth Amendment, ratified in 1865, formally abolished slavery and involuntary servitude throughout the United States, except as punishment for a crime.1

While President Abraham Lincoln issued the Emancipation Proclamation in 1863, that executive order functioned primarily as a military strategy during the American Civil War. It only applied to enslaved people in the Confederate States of America, leaving the legal status of slavery in border states and other territories uncertain.1

The Thirteenth Amendment provided a permanent, national solution by enshrining abolition in the Constitution of the United States. It effectively nullified previous constitutional provisions that had tacitly protected the institution of slavery, such as the Three-Fifths Compromise and the mandate to return escaped enslaved persons. By establishing this as a constitutional mandate, the amendment transformed emancipation from a wartime measure into a universal national policy, marking the first of the Reconstruction era amendments aimed at addressing the systemic inequities of slavery.1