What was the long term impact on history of the Americans of the death of large number of native Americans

How did the growth of the middle class affect social reform during the industrial revolution?

Who was in charge of american troops during world war i?

The idea of manifest destiny simply stated it was america's destiny to expand from the atlantic ocean to the pacific. the word "destiny" implies an idea that it was within our rights as a nation to expand. in a paragraph of 125+ words, explain what could be wrong with that idea.