It was December 18, 1865, when the 13th Amendment — which banned most slavery in all of the nation became part of the U.S. Constitution. Lincoln, the film, was realistic enough to show that a lot of what was done to get it passed was not pretty. Ratification was even worse. The ratification of the 13th Amendment, the 14th Amendment (promising equal protection of the law), and the 15th Amendment (guaranteeing the right to vote)…