Which policy or doctrine announced in the early 19th century warned European powers not to colonize the Western Hemisphere and was enforced by the United States?

Which policy or doctrine announced in the early 19th century warned European powers not to colonize the Western Hemisphere and was enforced by the United States?

• A. Monroe Doctrine
• B. Mercantilism
• C. Fort Taylor Doctrine
• D. Open Door Policy

Answer: (A)

The main idea this question tests is a long‑standing stance in U.S. foreign policy about the Western Hemisphere: no new colonization by European powers and the United States taking responsibility to defend that principle. This approach was announced in 1823, by President James Monroe, with strong input from his secretary of state, John Quincy Adams. The Monroe Doctrine stated that the Americas should be free from further European colonization and that European powers should not intervene in Latin American affairs. In return, the United States pledged that it would not meddle in European wars or politics. This established a clear expectation that any attempts to colonize or reassert control in the Americas would be viewed as a threat by the United States, and it laid the groundwork for U.S. influence in the region for many years to come. Other options don’t fit because they address different ideas or timeframes. Mercantilism focuses on economic policies about accumulating wealth through trade and colonies, not a hemispheric policy announced in the early 1800s. The Open Door Policy concerns China around the late 19th century, not the Western Hemisphere. A term like Fort Taylor Doctrine isn’t the established doctrine tied to this hemispheric warning. So the Monroe Doctrine best matches both the historical moment and the content of the policy described.

The main idea this question tests is a long‑standing stance in U.S. foreign policy about the Western Hemisphere: no new colonization by European powers and the United States taking responsibility to defend that principle. This approach was announced in 1823, by President James Monroe, with strong input from his secretary of state, John Quincy Adams. The Monroe Doctrine stated that the Americas should be free from further European colonization and that European powers should not intervene in Latin American affairs. In return, the United States pledged that it would not meddle in European wars or politics. This established a clear expectation that any attempts to colonize or reassert control in the Americas would be viewed as a threat by the United States, and it laid the groundwork for U.S. influence in the region for many years to come.

Other options don’t fit because they address different ideas or timeframes. Mercantilism focuses on economic policies about accumulating wealth through trade and colonies, not a hemispheric policy announced in the early 1800s. The Open Door Policy concerns China around the late 19th century, not the Western Hemisphere. A term like Fort Taylor Doctrine isn’t the established doctrine tied to this hemispheric warning. So the Monroe Doctrine best matches both the historical moment and the content of the policy described.