Wilmot Provison (dec 12, 1846 – jul 18, 1850)

Description:

The Wilmot Proviso was designed to eliminate slavery within the land acquired as a result of the Mexican War (1846-48). Proposed by David Wilmot (D-FS-R PA), if passed, the Proviso would have outlawed slavery in territory acquired by the United States as a result of the war, which included most of the Southwest and extended all the way to California.

Wilmot spent two years fighting for his plan. The Wilmot Proviso passed in the House of Representatives several times, but never in the Senate and so never became a law.
Nevertheless, the intensity of the debate surrounding the Proviso prompted the first serious discussions of secession.

Added to timeline:

Date: