Polk and others saw the acquisition of Texas, California, Oregon, and other territories as part of the nation's Manifest Destiny to spread democracy over the continent. The U.S. also tried to buy Texas and what was called “Mexican California” from Mexico, which was seen as an insult by Mexico, before war broke out.
Polk wanted a wider war with Mexico, and he wanted it to be wide enough so that a victory would allow the United States to annex all of Mexico's northern territory out to the Pacific ocean. It wasn't about settling the Texan border dispute, hence the lack of a treaty negotiated in good faith.
The correct answer is: c) Mexican Cession In the Treaty of Guadalupe Hidalgo, signed in 1848 after the U.S.-Mexican War, the United States acquired the Mexican Cession. The Mexican Cession included present-day states such as California, Nevada, Utah, most of Arizona, New Mexico, and parts of Colorado and Wyoming.
Treaty of Guadalupe Hidalgo. The Treaty of Guadalupe Hidalgo officially ended the Mexican–American War (1846–1848). It was signed on 2 February 1848 in the town of Guadalupe Hidalgo. See also the military convention of 29 February 1848 (5 Miller 407; 9 Bevans 807).
By its terms, Mexico ceded 55 percent of its territory, including the present-day states California, Nevada, Utah, New Mexico, most of Arizona and Colorado, and parts of Oklahoma, Kansas, and Wyoming.
In MacKay v. Campbell,t 6 U.S. v. Osborne, 7 and Elk v. Wilkins,1 8 the western courts ruled that Indians were not yet citizens and that the Fourteenth and Fifteenth Amendments did not apply to them.
The Fifth and Fourteenth Amendments both contain a Due Process Clause, although the Fourteenth Amendment applies explicitly to the states.
The principle is stated in the Fourteenth Amendment to the Constitution: "No State shall deny to any person within its jurisdiction the equal protection of the laws." This is referred to as the “Equal Protection Clause.”
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.
No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.