A possible claim for the Mexican American War could be that it was driven by U.S. expansionist ambitions to acquire more territory and resources. The U.S. government and many American citizens desired to expand westward and believed in the concept of Manifest Destiny, the belief that it was their destiny and duty to spread their way of life across the continent. This ambition led to conflicts over the annexation of Texas and the disputed border between Mexico and the U.S.
