President Abraham Lincoln’s Emancipation Proclamation, that came into force in 1863, ended slavery in the Confederate States that were at war with the Union. However, other states that remained loyal yet still operated slavery were not affected. Nevertheless, the Emancipation Proclamation encouraged abolitionists to find a way to end slavery in every state through a constitutional amendment.
Three separate proposals for an amendment banning slavery were introduced by Representatives James Ashley of Ohio and James Wilson of Iowa, and Senator John Henderson of Missouri. The Senate Judiciary Committee subsequently presented an amendment proposal to the Senate in early 1864. Despite finding support in the Senate, it nevertheless twice failed to secure the necessary two-thirds majority in the House of Representatives.
At the end of the year Lincoln won re-election, having announced that he intended to abolish slavery by constitutional amendment. The Republican Party also made gains in both the House and the Senate, which they claimed was a mandate for abolition. Nevertheless it was still necessary to secure votes from Democrats, and various legislators including Secretary of State William H. Seward lobbied and sometimes promised government jobs to outgoing politicians in return for votes.
Finally, on 31 January 1865, the amendment was passed by the House of Representatives with a vote of 119-56. It was sent to the states for ratification the next day, a process that was concluded on 6 December after the necessary three-quarters of states approved it.
