The Mexican-American war was a bloody and grisly battle between two major powers with the annexation of Texas and the protection and acquisition of territory. Mexico had inherited the provinces of California, New Mexico and Texas from Spain. Weakened and practically in bankruptcy after the war, the new mexican government was unable to rule its territories in the north thousands of kilometers from the capital (Greenberg). During its slow recovery, Mexico permitted a few hundred Americans to move into its territories. There were American colonies in some areas of Texas and New Mexico,The Austin Family asked Mexico for permission to create an American colony in the heart of Texas. They were granted permission to colonize under the conditions that they become Mexican citizens, learned spanish and converted to catholicism (Greenberg). When Americans began colonizing in this territory they promoted American culture and expansion. This led to many problems and tensions between the two countries, but these tensions were not the cause of the Mexican-American War. The invasion of Mexico was an act of expansionist aggression fueled by the hunger to gain as much land as possible. As it is apparent, The economic ambitions and Manifest Destiny mentality of the United States played the most significant role in creating a conflict between Mexico and the United States and starting the Mexican-American War. .
With more and more Americans moving into Texas, the territory seemed promising to newly elected United States President James K. Polk (Mexican-American War (Causes)). The expansionist mentality of the United States led Polk to try and acquire Texas. Polk attempted several times to convince Mexican Leader Santa Anna to sell it but he refused. On top of this, Americans living in Texas had a long list of fallacious complaints against mexico. The tensions began when Americans became angry that they had to learn Spanish and that all important documents were in spanish.