The 13th amendment, which formally abolished slavery in the United States, passed the Senate on April 8, 1864, and the House on January 31, 1865. On February 1, 1865, President Abraham Lincoln approved the Joint Resolution of Congress submitting the proposed amendment to the state legislatures.he 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 the Congress. Although the Senate passed it in April 1864, the House did not.