The Monroe Doctrine was an early 19th‑century U.S. foreign policy that warned European powers not to establish new colonies or interfere in the affairs of countries in the Western Hemisphere, while also pledging that the United States would stay out of European wars and existing European colonies in the Americas. It was first stated by President James Monroe in his annual message to Congress on December 2, 1823, and became a long‑term cornerstone of U.S. policy toward Latin America and the broader Western Hemisphere.
