Final answer:
The Monroe Doctrine extended and continued American foreign policy by endorsing interventionism.
Step-by-step explanation:
The Monroe Doctrine extended and continued American foreign policy by endorsing interventionism. The doctrine, outlined by President James Monroe in 1823, asserted that the United States would prevent future European colonization in the Western Hemisphere and would not tolerate European interference in the affairs of independent countries in the region. This stance demonstrated the United States' willingness to intervene in the affairs of Latin American nations whenever it believed assistance was necessary, as seen with the later addition of the Roosevelt Corollary in 1904.