While expanding westward was in the country's interests during the early 1800s, it wasn't until Andrew Jackson's election that Manifest Destiny, the idea that mainland America belonged to whites, really came to the forefront of United States policy. The idea of mainifest destiny was first developed by John L. O'Sullivan, a well-known advocate of Jacksonian Democracy. O'Sullivan believed it was America's "divine destiny" to settle westward and "establish on earth the moral dignity and salvation of man." This belief that it was our duty to settle mainland America created a superiority complex in Americans, which was on display when Andrew Jackson passed the Indian Removal Act. Not only was the act used to clear land for white settlement, but Jackson also passed the act due to his belief that the Natives could never be as "civilized" as whites.