The Monroe Doctrine was put into effect in 1823 and stated that further colonization attempts in the Americas by European countries would be seen as acts of aggression by the United States. It aimed to prevent European powers from interfering with or taking control of newly independent Latin American countries. While the Monroe Doctrine itself did not give the United States enough military power to enforce it, the agreement of Britain allowed it to succeed by keeping Britain focused on expanding its control in other parts of the world like Africa.