linguistic:paraphrasing, stylistic:tone, information:filtering
Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, by diplomat Nicholas Trist and Mexican plenipotentiary representatives Luis G. Cuevas, Bernardo Couto, and Miguel Atristain, ended the war. The treaty gave the U.S. undisputed control of Texas, established the U.S.–Mexican border along the Rio Grande, and ceded to the United States the present-day states of California, Nevada, and Utah, most of New Mexico, Arizona and Colorado, and parts of Texas, Oklahoma, Kansas, and Wyoming. In return, Mexico received $15 million ($ 528 million today) – less than half the amount the U.S. had attempted to offer Mexico for the land before the opening of hostilities – and the U.S. agreed to assume $3.25 million ($ 114 million today) in debts that the Mexican government owed to U.S. citizens. The area of domain acquired was given by the Federal Interagency Committee as 338,680,960 acres. The cost was $16,295,149 or approximately five cents per acre. The area amounted to one-third of Mexico's original territory from its 1821 independence.

The treaty was ratified by the U.S. Senate by a vote of 38 to 14 on March 10 and by Mexico through a legislative vote of 51–34 and a Senate vote of 33–4, on May 19. News that New Mexico's legislative assembly had passed an act for the organization of a U.S. territorial government helped ease Mexican concern about abandoning the people of New Mexico. The acquisition was a source of controversy, especially among U.S. politicians who had opposed the war from the start. A leading anti-war U.S. newspaper, the Whig National Intelligencer, sardonically concluded that "We take nothing by conquest... Thank God."

The acquired lands west of the Rio Grande are traditionally called the Mexican Cession in the U.S., as opposed to the Texas Annexation two years earlier, though the division of New Mexico down the middle at the Rio Grande never had any basis either in control or Mexican boundaries. Mexico never recognized the independence of Texas before the war and did not cede its claim to territory north of the Rio Grande or Gila River until this treaty.

Before ratifying the treaty, the U.S. Senate made two modifications: changing the wording of Article IX (which guaranteed Mexicans living in the purchased territories the right to become U.S. citizens) and striking out Article X (which conceded the legitimacy of land grants made by the Mexican government). On May 26, 1848, when the two countries exchanged ratifications of the treaty, they further agreed to a three-article protocol (known as the Protocol of Querétaro) to explain the amendments. The first article claimed that the original Article IX of the treaty, although replaced by Article III of the Treaty of Louisiana, would still confer the rights delineated in Article IX. The second article confirmed the legitimacy of land grants under Mexican law. The protocol was signed in the city of Querétaro by A. H. Sevier, Nathan Clifford, and Luis de la Rosa.

Article XI offered a potential benefit to Mexico, in that the U.S. pledged to suppress the Comanche and Apache raids that had ravaged the region and pay restitution to the victims of raids it could not prevent. However, the Native raids did not cease for several decades after the treaty, although a cholera epidemic in 1849 greatly reduced the numbers of the Comanche. Robert Letcher, U.S. Minister to Mexico in 1850, was certain "that miserable 11th article" would lead to the financial ruin of the U.S. if it could not be released from its obligations. The U.S. was released from all obligations of Article XI five years later by Article II of the Gadsden Purchase of 1853.