"What do you think of the treaty?"
Cover of the exchange copy of the treaty of Guadalupe Hidalgo
Public DomainCover of the exchange copy of the treaty of Guadalupe Hidalgo - Credit: National Archives and Records Administration

This is a reference to the Treaty of Guadalupe Hidalgo, the peace treaty, largely dictated by the United States to the interim government of a militarily occupied Mexico City, that ended the Mexican-American War on February 2, 1848.

Under the terms of the treaty, Mexico ceded to the United States Upper California and New Mexico. This was known as the Mexican Cession and included all of present-day California, Nevada and Utah as well as most of Arizona, New Mexico and Colorado. Mexico relinquished all claims to Texas and recognized the Rio Grande as the southern boundary of the United States.