In: Economics
Mexico did not follow its threat of declaring war, relations between the two nations remained strained over border disputes, and in July 1845, President Polk ordered troops into disputed lands between the rivers Nueces and Rio Grande. In November, Polk sent the diplomat John Slidell (1793-1871) to Mexico to request boundary changes in exchange for the resolution of American citizens' claims against Mexico by the U.S. government, and also to make an offer to buy California and New Mexico. The U.S. has missing the attempt Under General Zachary Taylor (1784-1850) the army advanced to the mouth of the Rio Grande, the river claimed by the State of Texas as its southern boundary
Mexico, arguing that the border was the Nueces Riverto to the northeast of the Rio Grande, deemed Taylor 's army advance an act of provocation and sent troops across the Rio Grande in April 1846. Polk, in turn, declared the Mexican advance to be an invasion of U.S. soil, and asked Congress on May 11, 1846 to declare war on Mexico, two days later.
Following the Mexican army 's defeat and the fall of Mexico City, the Mexican government surrendered in September1847 and peace negotiations began. The war formally concluded with the signing of the Treaty of Guadalupe Hidalgo in Mexico on 2 February 1848. The treaty added another 525,000 square miles to the territories of the United States, including the land that forms all or portions of present-day Arizona , California , Colorado, Nevada , New Mexico, Utah and Wyoming. Mexico also relinquished all claims to Texas and acknowledged the Rio Grande as the southern frontier of America. The U.S. paid Mexico $15 million in exchange, and agreed to settle all U.S. citizens' lawsuits against Mexico.