Question

What movement was in favor of U.S. expansion in Latin America?

Answer 1

What movement was in favor of U.S. Expansion in Latin America?
I would say Young America. 

Answer 2

Credits to :HistoryGuy  Ambitious  Young American" movement that was in favor of U.S. expansion in Latin America, although it should be noted that there were others who were in favor of such expansionism as well.