Answer:
In a speech to Congress in 1823, President James Monroe warned European powers not to attempt further colonization or otherwise interfere in the Western Hemisphere, stating that the United States would view any such interference as a potentially hostile act. Later known as the Monroe Doctrine, this policy principle would become a cornerstone of U.S. diplomacy for generations.
U.S. Motivations Behind the Monroe Doctrine
By the early 1820s, many Latin American countries had won their independence from Spain or Portugal, with the U.S. government recognizing the new republics of Argentina, Chile, Peru, Colombia and Mexico in 1822. Yet both Britain and the United States worried that the powers of continental Europe would make future attempts to restore colonial regimes in the region. Russia had also inspired concerns of imperialism, with Czar Alexander I claiming sovereignty over territory in the Pacific Northwest and banning foreign ships from approaching that coast in 1821.