The 13th Amendment was officially proclaimed in effect

On December 18, 1865, Secretary of State William H. Seward proclaimed that the Thirteenth Amendment had been ratified and was now part of the United States Constitution. With that certification, slavery and involuntary servitude — except as punishment for a crime — were abolished across the nation.

The legal machinery had moved quickly that month. Congress had passed the amendment on January 31, 1865, and the states completed ratification on December 6, 1865, when the required three-quarters threshold was reached. Seward’s proclamation twelve days later was the formal announcement that made it official.

One sentence in the Constitution undid an institution that had stood for more than two centuries.

The amendment did not, by itself, secure equal citizenship; that work fell to the Fourteenth and Fifteenth Amendments and to a long fight that followed. But December 18 marks the moment abolition stopped being a wartime measure and became the country’s supreme law.