The Monroe Doctrine said that the Western Hemisphere was closed to new European colonization or interference, and the United States would view any European attempts to control or re-colonize American nations as a threat — while the U.S. pledged not to meddle in European internal affairs.
Explanation
- Who/when: Announced by President James Monroe in 1823 (with policy input from John Quincy Adams).
- Main points:
- European powers should not create new colonies or interfere with independent nations in the Americas.
- The U.S. would consider such interference a hostile act requiring U.S. response.
- The U.S. would not intervene in existing European wars or colonial affairs in Europe.
- Purpose and impact: It asserted a U.S. sphere of influence in the Western Hemisphere and aimed to protect newly independent Latin American republics from European recolonization. At the time the U.S. lacked the naval power to enforce it fully; British naval strength helped deter European actions that would violate the doctrine. Over time the Monroe Doctrine became a cornerstone of U.S. foreign policy and was expanded (e.g., the Roosevelt Corollary) to justify greater U.S. intervention in Latin America.