The Wilmot Proviso
August 12, 1846
Provided, That, as an express and fundamental condition to the acquisition of any territory from the Republic of Mexico by the United States, by virtue of any treaty which may be negotiated between them, and to the use by the Executive of the moneys herein appropriated, neither slavery nor involuntary servitude shall ever exist in any part of said territory, except for crime, whereof the party shall first be duly convicted.
The Wilmot Proviso above was passed by the House of Representatives but not by the Senate. Although it never went into effect, it was debated and discussed many times over the following months and years. The Issue of slavery in the territory acquired from Mexico was fianlly settled in the Compromise of 1850, but even that compromise had only a temporary effect. The issue would ntot go away.