The Monroe Doctrine, proclaimed by President James Monroe in 1823, asserted that the Western Hemisphere was off-limits to further European colonization and interference.

It aimed to protect newly independent nations in Latin America from European powers seeking to expand their influence.The doctrine conveyed that any attempt by European nations to assert control or colonize the Americas would be considered a threat to U.S. security, justifying potential intervention. This policy marked a significant shift in U.S. foreign relations, establishing the nation as a dominant force in the Western Hemisphere and laying the groundwork for future American interventions in the region.