When it comes to the us becoming a imperial power, their main goal was economic expansion. now their ideals were good but since they started being an imperial power the economy has gone rather worse. so to answer your question their goals were good not have not been achieved.
That could definitely be argued! The WWI was fought in Europe, so many European countries were left in pieces at its end. So they were definitely in need of outside support. One may also look at it from another point of view. The US refused to join the League of Nations, which shows that the country was not necessarily as involved in world affairs as it could have been.
The American Colonization Society (ACS) was formed in 1817 to send free African-Americans to Africa as an alternative to emancipation in the United States.
