Because they believed that God wouldn’t let anything happen to them(at least most of them)
So their faith was so strong that they weren’t afraid of what was happening
I think the answer is colonization. Many European countries like Great Britain, France, Spain, and Portugal had started exploring the New World. These European Nations wanted to expand their territory and to spread religion and civilized barbarians in their colony.
The United States menifested its destiny by trying to expand from coast to coast. But first the americans have to kick out the native americans because the native americans are in there land and is blocking there way to menifest.
So your answer would be <span>acquired all the land between the Atlantic and Pacific Oceans</span>
