Slavery was gradually ended in the United States during the Civil War. At first Congress ended slavery in the US territories. Abraham Lincoln’s Emancipation Proclamation only ended slavery in the Confederacy. It did not affect slavery in the border states which remained in the Union. Kentucky was an example of one of these states in which slavery was allowed to continue. The complete end of slavery did not occur in the United States until the ratification of the 13th amendment after the Civil War.
(The Great Courses – The History of the United States)
An interesting fact relevant to your post:
“The 13th Amendment to the Constitution, which abolished slavery, was ratified in 1865. Lawmakers in Mississippi, however, only got around to officially ratifying the amendment last month (January 2013) — 148 years later — thanks to the movie “Lincoln.”
A “slight” oversight?