An effort by Congress to defuse the sectional and political rivalries triggered by the request of Missouri late in 1819 for admission as a state in which slavery would be permitted.
The Wilmot Proviso was designed to eliminate slavery within the land acquired as a result of the Mexican War. The conflict over the proviso was one of the major events leading to the American Civil War.
Compromise of 1850
The Compromise of 1850 was a package of five separate bills passed by the United States Congress which caused a four-year political confrontation between slave and free states regarding the status of territories acquired during the Mexican–American War.
The Kansas-Nebraska Act was passed by the U.S. Congress on May 30, 1854. It allowed people in the territories of Kansas and Nebraska to decide for themselves whether or not to allow slavery within their borders.
Dred Scott V. Sandford
In Dred Scott v. Sandford the Supreme Court ruled that Americans of African descent, whether free or slave, were not American citizens and could not sue in federal court.