The 1823 Treaty, also known as the Monroe Doctrine, was a significant policy statement by the United States. It declared that any European intervention in the Americas would be viewed as an act of aggression, prompting U.S. intervention. This doctrine aimed to protect newly independent nations in Latin America from European colonialism. The treaty was articulated by President James Monroe during his annual address to Congress. It established a clear boundary between the Americas and Europe, asserting that the Western Hemisphere was no longer open to colonization. This policy laid the groundwork for future U.S. foreign relations in the region.