Manifest Destiny was a doctrine that implied that the United States had the divine right (i.e. the God-given right) to expand to the Pacific Ocean. The central basis of this position was that the US had a divine right to accumulate across the continent of North America and into the Pacific Ocean. A newspaper man named John L. O'Sullivan first used the term in 1845. President James K. Polk ran on a platform of what would be called Manifest Destiny. A belief in Manifest Destiny led to the U.S. fighting the Mexican-American War. This belief continued to play a key role in the United States settlement of western lands, especially in the rush to California and in the U.S. taking over Oregon.