The answers are in Plato goes like this
declared Cuba a US protectorate ---> Platt Amendment
stated that European interference in the
Western Hemisphere would be treated
as an act of aggression -----> Monroe Doctrine
stated that the United States would act as
a police force for economic disputes between
Latin America and Europe ----> Roosevelt's Corollary
helped the United States reduce time and
costs related to trade ----> Panama Canal
How it is done in Plato.