Wilmot Proviso

The Wilmot Proviso proposed an American law to ban slavery in any territory acquired from Mexico in the Mexican War. The conflict over the proviso was one of the major events leading to the American Civil War.

Congressman David Wilmot first introduced the proviso in the United States House of Representatives on August 8, 1846, as a rider on a $2,000,000 appropriations bill intended for the final negotiations to resolve the Mexican–American War (this was only three months into the two-year war). It passed the House but failed in the Senate, where the South had greater representation. It was reintroduced in February 1847 and again passed the House and failed in the Senate. In 1848, an attempt to make it part of the Treaty of Guadalupe Hidalgo also failed. Sectional political disputes over slavery in the Southwest continued until the Compromise of 1850.