In killing Native Americans, Carson was making America safe for settlers heading west to build their homes, farms, and villages. He had the approval of the United States government and its citizens. In addition, Senator Thomas Hart Benton, the United States Congress, and President James K. Polk had developed and were working under a concept called Manifest Destiny. This concept stated that it was the will of God that the United States push America's western boundary to the Pacific Ocean at all costs. Manifest Destiny spurred the movement of American settlers to the West.