What is the Monroe Doctrine?

The Monroe Doctrine

The Monroe Doctrine was a U.S policy that opposed European colonization and prohibited European powers from interfering with the affairs of the western hemisphere. On December 2,1823 President James Monroe articulated this doctrine in his annual message to congress. However it was not until 1856 that the doctrine was actually invoked when the U.S. government exerted diplomatic and military pressure in support of the Mexican President Benito Juárez. This support enabled Juárez to lead a successful revolt against the Emperor Maximilian, who had been placed on the throne by the French government.