In U.S. history, what was the primary purpose of the Monroe Doctrine?

• A. To oppose European colonization in the Western Hemisphere and to assert U.S. influence in the Americas
• B. To promote European colonization in the Western Hemisphere
• C. To escalate military alliances in Europe
• D. To regulate American trade with Asia

Answer: (A)

The Monroe Doctrine is about defending the Western Hemisphere from European encroachment while establishing the United States as the dominant influence there. It warned European powers to stop colonization in the Americas and to leave newly independent republics alone, signaling that the Americas should be off-limits to new European colonization. At the same time, it stated that the United States would stay out of European wars and avoid entangling alliances, effectively drawing a line around the Western Hemisphere and asserting U.S. influence within it. This combination—opposing European colonization and signaling U.S. leadership in the Americas—is why this choice best captures the doctrine’s purpose. It isn’t about promoting colonization, building European alliances, or regulating Asia trade.