noun U.S. History.
- the policy, as stated by President Monroe in 1823, that the U.S. opposed further European colonization of and interference with independent nations in the Western Hemisphere.
- a principle of US foreign policy that opposes the influence or interference of outside powers in the Americas
1848, in reference to principles of policy contained in the message of U.S. President James Monroe to Congress on Dec. 2, 1823. A statement of foreign policy issued by President James Monroe in 1823, declaring that the United States would not tolerate intervention by European nations in the affairs of nations in the Americas. Monroe also promised that the United States would not interfere with European colonies already established or with governments in Europe.