Collection of circulars, pamphlets, speeches, and other ephemera related to the Wilmot Proviso. The Wilmot Proviso was introduced in the United States House of Representatives on August 8, 1846 by Congressman David Wilmot as a provision of an appropriations bill. The proviso sought to ban slavery in any territory acquired from Mexico as a result of the Mexican-American War. The bill passed in the House but failed in the Senate. Although it did not pass into law, the Wilmot Proviso is credited with intensifying the slavery debate in the years leading up to the Civil War.