Mexico had long insisted that its northern border lay along the Nueces River. The United States claimed the border was further south, along the Rio Grande. In June 1845, President Polk ordered General Zachary Taylor to lead an army into the challenged region. I think the United States should not have entered the Mexican-American War because the northern part of the United States had political interests against adding a new slave state. The Mexican government also wanted raids on the border and warned that any attempted takeover would lead to war. I think it is unjustified to provoke a war over a borderland. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay America is trying to grow and get more land, so when they were offered to buy land off the coast of Mexico it was not supposed to be a threat or a way to anger Mexico. The United States believes that it can do the job itself and that it is unfair to have other human beings do it for them. In the north there is also fear of the spread of slavery into the lands of the southwest. Mexico was rightly trying to quell a rebellion in Texas, and the Americans intervened on Texas's behalf. President Polk believed that the clear destiny of the United States was to expand across the continent to the Pacific Ocean. Overall there were many cultural differences between the Mexican and American settlers in the area. Also Mexico's refusal to admit Texas' independence and entry into the United States. I think the Mexican-American War had such a tremendous impact on the tension between the Northern and Southern states during the pre-Civil War era. I think this because this war marked the first American armed conflict fought on foreign soil. He pitted a politically divided and militarily unprepared Mexico against the administration of U.S. President James K. Polk. The fight took place along the Rio Grande and began fighting, followed by numerous US victories. Mexico had lost about 1/3 of its territory, including nearly all of present-day California, Utah, Nevada, Arizona, and New Mexico. In February 1848, the United States and Mexico signed the Treaty of Guadalupe Hidalgo, which officially ended the war and forced Mexico to cede much of its northern territory to the United States. I think this is a very important part in history and has influenced the life we ​​live today.