Manifest Destiny played a big role in the settling of the West and in fighting the Mexican-American War. Manifest Destiny means it was meant to be that we would settle the west. It was only natural for us to settle the land between the Atlantic and Pacific Oceans. As a result of this belief, we began to move westward. We believed our way of life was superior, and we had an obligation to spread that way of life. First we moved the Native Americans west of the Mississippi River so we could expand to the Mississippi River. Then we moved the Native Americans onto reservations as we spread to the Rocky Mountains. We also helped Texas in its revolution against Mexico. We believed we had to control the southwest part of our country so we could spread our superior way of life. Thus, we got into a war with Mexico that gave us the southwest. The belief in Manifest Destiny was a big part of our expansion from the Atlantic Ocean to the Pacific Ocean.