Question

what was manifest destiny

Answer 1

Manifest Destiny was the 19th century American belief that the United States was destined to expand across the continent. It was used by Democrat-Republicans in the 1840s to justify the war with Mexico; the concept was denounced by Whigs, and fell into disuse after the mid-19th century.

Answer 2

also it was that the US thought that God himself thought that the US should stretch from "sea to shining sea," and later in the 19th century the Philippines, Guam, Hawaii, Wake Islands, for more land.