The Mexican American War

This war was caused by Polk's views to increase the territory that the United States owned, along with the annexation of Texas. James K. Polk wanted to buy the lands west of Texas, but this offer was declined by Mexico. Polk sent troops to the area between the Rio Grande and Nueces Rivers, which was stated earlier as a site of a dispute between Mexico and Texas concerning the borders. This battle infuriated Congress, and on May 13th, they declared war on Mexico. The Mexican side suffered many losses, and toward the end, they called in General Santa Anna. The general said that the war would end and would benefit the United States, but instead, Santa Anna took control of the Mexican army and took it to war against the United States. The Mexican side was obliterated, and the Treaty of Guadalupe Hidalgo was signed.