CLEP US History II

Answer: A - The Monroe Doctrine, introduced in 1823 by President James Monroe and his Secretary of State, John Quincy Adams, declared that further European colonization or interference in North or South America would be construed as an act of war against the United States, effectively declaring American dominion over the Western Hemisphere. The policy was later used as justification for American expansion throughout the rest of the century and well into the next, until the period of American expansionism came to an end.