Manifest Destiny played a huge role in American foreign policy. It led to treaty negotiations with Britain over the ownership of the Oregon Territory. Manifest Destiny also led the United States to invade Mexico and then seize much of the West after the successful Mexican War.There were also negative effects of Manifest Destiny.
answerThis idea that it was their destiny to expand caused Americans to disregard the territorial rights of Native Americans, wiping out many tribes and causing a cultural divide, tension and wars. The negative effect that this had on Native Americans were lasting effects. Manifest Destiny also caused war and tension with Mexico for the same reasons. Manifest Destiny caused americans to feel entitled, greedy, power hungry, they wanted to be the best, which are poor qualities to have. Another negative effect was the affect this had on slavery. With the expansion came more farms, which in turn meant a greater need for slave workers, although Manifest Destiny later brought on debates about slaves, helping to end slavery.
