.Why was the idea of Manifest Destiny important to many Americans?

It was shown that the Americans were blessed by God(if you aren't Christian or Jewish, then you won't under stand who God is) to expand, and dominate, practically saying that the Americans are superior, and it is destined for them to be the first and only country to span across a continent.

it was a act of seld fesnse more over it was a peace treaty between the fogein contunries.