David Wilmot was a Pennsylvania-born congressman who opposed slavery. His "proviso"—a clause tacked on to a number of legislation being debated in Congress—prohibited slavery in all of the new territory won from Mexico following the Mexican War. Although the proviso was well-liked in the North, it was vehemently opposed by the South and never became a part of the legislation. It declared that slavery would be outlawed in any new area that the United States might take over from Mexico. The argument over whether slavery still exists in the West was rekindled.
