After watching the film, which depicts the political fight to pass the 13th Amendment, Batra did some research. He learned that the amendment was ratified after three-fourths of the states backed it in December 1865. Four remaining states all eventually ratified the amendment -- except for Mississippi. Mississippi voted to ratify the amendment in 1995 but failed to make it official by notifying the U.S. Archivist.
After 148 years, Mississippi finally ratifies 13th Amendment, which banned slavery - CBS News
Waiting until 1995 was funny enough but 2013 made my day. Way too funny.