The Mexican-American War occurred from 1846-1848. On February 2, 1848, the Treaty of Guadalupe Hidalgo was signed at the city of Guadalupe Hidalgo, Mexico bringing an official end to the war. With the defeat of the Mexican army and the fall of Mexico City in September of the previous year, the Mexican government chose to surrender to the United States.
The peace talks were negotiated by Nicholas Trist who was the chief clerk of the State Department. At first, Trist along with General Winfield Scott tried to negotiate with Mexican President Santa Anna. However, after two attempts, they decided that they needed to deal with Mexico as a conquered enemy. Trist negotiated with a special commission led by Don Bernardo Couto, Don Miguel Atristain, and Don Luis Gonzaga Cuevas.
However, confusion arose when President James K. Polk
recalled Trist back to Washington. He believed that the negotiations would be carried out there. However, it took six weeks to deliver Polk's message. During that time, Trist began working with the special negotiation commission. He decided that President Polk did not understand the issues that had arisen over the negotiations. He negotiated the treaty without returning to Washington, in defiance of the President.
Terms of the Treaty of Guadalupe Hidalgo
By the terms of the Treaty of Guadalupe Hidalgo, Mexico ceded 55 percent of its territory, including parts of present-day Arizona, California, New Mexico, Texas, Colorado, Nevada, and Utah, to the United States. In exchange, the US paid Mexico $15,000,000 "in consideration of the extension acquired by the boundaries of the United States." Additional provisions included protecting property and civil rights of Mexican nationals living within the new boundaries of the US along with the promise of the US to police its borders.