14. Mexican War The Mexican War was a controversial war that fulfilled the American belief of manifest destiny. The three major causes of the war were the Texas Revolution, the inability of Mexico to establish firm political control of its northern regions, and the expansionist movement in the United States.
Mexico had trouble keeping control of its northern territory. In 1823, the Mexican government made a deal with Stephen Austin to bring in three hundred American families to Texas and they were to join the Catholic Church and to become citizens of Mexico. However, tensions soon began to grow between the immigrants and the Mexican government. Mexico abolished slavery in 1830, but the American immigrants still kept their slaves and even kept bringing in more slaves. In 1835, the Mexican dictator, Santa Anna, took all local rights away from Texas and started to raise an army against the Texans. In 1836 the Texans declared their independence and war broke out with Mexico.
In the end the Texans won, with the help of American supplies and men.
Mexico was angry that the United States had helped Texas. In 1837, Texas applied for annexation to the United States, however it was turned down. The admission of another slave state would have triggered an explosion over the slavery issue. Also if America annexed Texas, Mexico would take it as an act of aggression.
President James K. Polk was elected in 1844 with a platform of manifest destiny. His predecessor President John Tyler interpreted his election as a mandate, by the American people, for the annexation of Texas and Tyler signed the resolution admitting Texas into the Union, just before he left the office. The admission of Texas caused Mexico to cut of relations with the U.S.
In order to complete his promises of...