Answer:
Divine mission.
Explanation:
The phrase in the question refers to the element of manifest destiny that refers to the divine mission of the United States to expand to the west. Under this concept, America had the divine permission to expand territorially, taking with it the progress and individual liberties created by the white man.
In itself, this idea is a fallacy that functioned as a moral justification for the expansion and displacement of native tribes to reservations. But in an era where faith and religious traditions were very strong, justification based on divine approval was reason enough for many people to support expansion.