In 1865, the House of Representatives finally passed the 13th Amendment to the Constitution, abolishing slavery in America.
In 1862, Abraham issued the Emancipation Proclamation freeing all slaves in the United States as of January 1, 1863. After the proclamation, Congress put together an amendment to the constitution. This change would keep the abolishment of slavery even if a new president challenged the proclamation.
In April of 1864, the Senate passed the 13th amendment, but the House did not. After re-election, Lincoln avidly campaigned for the amendment. Again the Senate passed it, but this time the House also passed the amendment in 1865. Thus all states and colonies under its jurisdiction could no longer have slavery or indentured servitude.