Nonetheless, the Emancipation Proclamation did'nt end slavery in the nation since it only applied to areas of the Confederacy currently in a state of rebellion (and not even to the loyal “border states” that remained in the Union).

Lincoln recognized that the Emancipation Proclamation would have to be followed by a constitutional amendment in order to guarantee the abolishment of slavery.

The 13th Amendment was passed at the end of the Civil War before the Southern states had been restored to the Union, and should have easily passed in Congress. However, though the Senate passed it in April 1864, the House initially did not. At that point, Lincoln took an active role to ensure passage through Congress. He insisted that passage of the 13th Amendment be added to the Republican Party platform for the upcoming 1864 Presidential election. His efforts met with success when the House passed the bill in January 1865 with a vote of 119–56.

On February 1, 1865, President Abraham Lincoln approved the Joint Resolution of Congress submitting the proposed amendment to the state legislatures. The necessary number of states (three-fourths) ratified it by December 6, 1865. The 13th Amendment to the United States Constitution provides that: