Ideas & Events: The Monroe Doctrine

While serving as secretary of state under President James Monroe, John Quincy Adams established one of the core principles of U.S. foreign policy: the Monroe Doctrine, which warned European powers not to intrude in the affairs of the Western Hemisphere.

The doctrine was first articulated in December 1823 during Monroe’s annual message to Congress. At the time, many of Spain’s colonies in Latin America were moving towards independence, and the U.S. wanted to discourage other European powers from stepping in. The doctrine stated “the American continents, by the free and independent condition which they have assumed and maintain, are henceforth not to be considered as subjects for future colonization by any European powers.” Furthermore, any efforts to interfere with states in the Americas would be seen as acts of aggression and would require U.S. intervention.

Protecting U.S. interests

The Monroe Doctrine has been invoked on many occasions, both to protect U.S interests in the hemisphere and to support expansionist ambitions.

  • In the 1840s, President James Polk cited it to justify westward settlement under the banner of Manifest Destiny.
  • In 1865, the U.S. extended support to Mexican President Benito Juárez, enabling a successful revolt against Emperor Maximilian, who had been placed on the throne by the French government.
  • In 1904, when European creditors threatened armed intervention in Latin America to collect outstanding debts, President Theodore Roosevelt proclaimed the U.S.’s right to exercise an “international police power” to curb such actions.
  • In 1962, during the Cuban missile crisis, President John F. Kennedy invoked the Monroe Doctrine as a justification for setting up a naval and air blockade around Cuba. In a tense standoff that brought the world to the brink of nuclear war, this action helped pressure the Soviet Union into dismantling and withdrawing nuclear missiles that had been secretly installed in Cuba and aimed at the U.S.