Treaty of Guadalupe Hidalgo Facts & Worksheets

• The US military strategy comprised three primary objectives: (1) to gain control of northern Mexico, encompassing New Mexico; (2) to seize California; and (3) to capture Mexico City. General Zachary Taylor and his Army of the Centre were tasked with achieving the initial objective, and with advanced weaponry, they swiftly seized the Mexican city of Monterrey. Taylor rapidly emerged as a hero among the American populace, leading to Polk’s appointment of him as commander of all US forces.
• General Stephen Watts Kearny, in charge of the Army of the West, accepted the surrender of Santa Fe, New Mexico. He then moved on to take control of California and gave Colonel Sterling Price command. Even though Kearny promised that the people of New Mexico did not have to worry about their lives or property, they rose up in January 1847 to try to drive the Americans out. Price was able to quell the rebellion, but tensions remained high.
• Kearny arrived in California to discover that it was already under American control, achieved through the collaborative efforts of California settlers, US naval commander John D. Sloat, and John C. Fremont, a former army captain and the son-in-law of Missouri Senator Thomas Benton. Sloat, anchored off the coast of Mazatlan, received news of the commencement of war and promptly departed for California. In July 1846, he captured the town of Monterey, shortly after American settlers led by William B. Ide had gained control of Sonoma and proclaimed California a republic. One week following the capture of Monterey, the navy seized San Francisco without encountering any opposition. In September 1846, a brief rebellion was initiated by certain Californios, while a significant number acquiesced to the US annexation. Kearny’s primary responsibility was to assume the role of governor of California.

DEBATE OVER THE TREATY OF GUADALUPE HIDALGO

• In May 1848, the Mexican Congress and President Manuel de la Peña y Peña met in Querétaro City, amidst the occupation of Mexico City. They confronted the challenge of negotiating a treaty while addressing the rising separatism and anarchy across the nation. The Caste War in Yucatán was characterised by insurgents occupying the major cities. Numerous states regarded the federal government as an adversary and declined to remit taxes. 
• In the Federal District, a significant Mexican faction supported the annexation of the entire nation to the US. The majority of Congress endorsed the government’s peace policy, perceiving the Treaty of Guadalupe Hidalgo as merely an unfortunate outcome of a poorly executed war, and regarded it, from this viewpoint, as a national necessity. The initial question was addressed based on the principle that Congress represents the repository of national sovereignty.
• The second question was addressed by noting that Mexico had never fully possessed the territories slated for cession, and that much of this land was either uninhabited or inhabited by hostile indigenous tribes. It was considered that Mexico could not sustain the war without encountering inevitable defeat and jeopardising the integrity of the nation. Following the commission's report, Congress approved the Treaty of Guadalupe Hidalgo. 
• President Peña y Peña formulated decrees aimed at preventing disorder in the capital following the departure of the occupiers and establishing a national guard. On 26 May 1848, the government received commissioners Nathan Clifford and Ambrose Hundley Sevier, who were in Mexico to negotiate the treaty following congressional approval with minor modifications. On 30 May 1848, following the exchange of ratifications of the Treaty of Guadalupe Hidalgo, the two countries engaged in further negotiations resulting in a three-article protocol to clarify the amendments.
• The initial article indicated that the original Article IX of the treaty, despite being supplanted by Article III of the Treaty of Louisiana, would continue to grant the rights specified in Article IX. The second article validated the legitimacy of land grants under Mexican law. The protocol indicated that the Mexican Minister of Foreign Affairs accepted the explanations on behalf of the Mexican Government, and it was signed in Querétaro by A. H. Sevier, Nathan Clifford, and Luis de la Rosa. The US subsequently disregarded the protocol, asserting that its representatives had exceeded their authority in consenting to it.

EFFECTS OF THE TREATY OF GUADALUPE HIDALGO

• The treaty not only facilitated the sale of land but also established the Rio Grande as the boundary between Texas and Mexico. The land boundaries were determined by a survey team composed of designated representatives from Mexico and the US, and documented in three volumes titled the United States and Mexican Boundary Survey. On 30 December 1853, the countries reached an agreement to modify the border, increasing the number of border markers from 6 to 53.
• The majority of these markers consisted of mere accumulations of stones. Subsequent conventions in 1882 and 1889 provided additional clarification of the boundaries, as several markers had been relocated or destroyed. Photographers were engaged to record the positions of the markers. The photographs are located in Record Group 77, which contains the Records of the Office of the Chief Engineers at the National Archives.
• The southern border of California is defined as a line extending from the confluence of the Colorado and Gila rivers westward to the Pacific Ocean, situated one Spanish league south of the southernmost point of San Diego Bay. This action aimed to secure San Diego and its superior natural harbour for the US. The treaty granted US citizenship to Mexicans in the newly acquired territories prior to the eligibility of many African Americans, Asians, and Native Americans. They were required to declare their choice to the US government within one year of the Treaty being signed; otherwise, they could retain their Mexican citizenship, contingent upon relocation. From 1850 to 1920, the US Census classified the majority of Mexicans as racially “white”. 
• In California and other western states, community property rights are derived from the Visigothic Code, which was adopted by Spain and subsequently introduced to the Americas, including the territories of Mexico ceded to the United States. While individual states had varying motivations for adopting the Spanish approach, a shared factor was its longstanding presence in the region. 
• The US acquired the territories of Alta California and Santa Fe de Nuevo México. Currently, they include some or all of the US states: Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. The land, although extensive, was largely sparsely populated, primarily inhabited by Indigenous Americans rather than white Americans or Mexicans.