The Monroe Doctrine, a key foreign policy statement in early American history, articulated a principle of U.S. opposition to European interference in the Western Hemisphere. Specifically, it declared that any further efforts by European powers to colonize or control independent states in North or South America would be viewed as a hostile act toward the United States. This principle became a cornerstone of American foreign policy, even if the nation lacked the immediate capacity to fully enforce it.
The significance of this declaration lies in its assertion of U.S. dominance in the Americas. It aimed to protect newly independent Latin American nations from European reconquest and to secure U.S. commercial and strategic interests in the region. Although initially limited by American power, it gradually evolved into a justification for U.S. intervention in Latin American affairs, shaping relations between the United States and its southern neighbors for over a century.