The Mexican war caused conflict within America. In 1836, after Mexico had won its independence from Spain, Texas rebelled against the Mexican government. Texas won its independence from Mexico with the help of US troop, but Mexico did not recognize the new Republic of Texas. The United States did not originally want any trouble with Mexico, and turned down Texas' request to join the Union but then this was later changed when Mexico refused to let the US purchase Texas. The US did not want to cause the war, so President Zachary Taylor waited for the Mexican government to initiate a spark of conflict. When Santa Anna, the Mexican general, and his troops passed the Rio Grande into Texas, it was reason enough to start war.
The Treaty of Guadalupe
The Treaty of Guadalupe