Monroe Doctrine. The Monroe Doctrine was a U.S. foreign policy regarding domination of the Americas in 1823. It stated that further efforts by Europeannations to colonize land or interfere with states in North or South America would be viewed as acts of aggression, requiring U.S. intervention.[1] At the same time, the doctrine noted that the United States would neither interfere with existing European colonies nor meddle in the internal concerns of European countries.
