Most Influential US Citizen in US Policy Toward Latin America?

I've been reading Lars Schoultz's new book In Their Own Best Interest: A History of the U.S. Effort to Improve Latin Americans. This bit intrigued me:

Meanwhile, [Nelson] Rockefeller set to work building his Office, the first formal U.S. foreign aid program, and for that reason he probably qualifies as the second-most influential citizen in the history of U.S. policy toward Latin America. (Theodore Roosevelt will always be first, and Fidel Castro would move Rockefeller into third if noncitizens were included) (p. 149).

This is a neat thought experiment. On the Latin America side, I don't think there is any doubt about Fidel Castro. Hugo Chávez is becoming a case of someone who seemed so influential but whose influence did not outlast him.

What about the U.S. side? Roosevelt was the reason for the Panama Canal, while also playing a role (albeit minor) in making Cuba a protectorate and then (more centrally) keeping it under U.S. control, while the Roosevelt Corollary established U.S. intervention as a doctrine. Rockefeller established the gargantuan system of foreign aid, building it from scratch.

Other possibilities:

James Monroe: U.S. president keep using his stated doctrine, even just this week. Maybe a nod to John Quincy Adams, who actually wrote it.

James Polk: taking Mexican territory created much of the U.S. West, became a critical engine of the U.S. economy, and set the tone for U.S.-Mexican relations from then on.

Allen Dulles: was behind the invasions of Guatemala and Cuba, which helped cement Fidel Castro and Che Guevara as icons, while encouraging greater interest by the Soviet Union.