Final answer:
The Monroe Doctrine is associated with 19th-century American nationalism and aimed to deter European interference in the Western Hemisphere, aiding U.S. interests in commerce and territorial expansion.
Step-by-step explanation:
The Monroe Doctrine is most closely associated with the 19th-century trend of promoting a nationalist vision and safeguarding the sovereignty of the Western Hemisphere from European colonial powers.
During the Era of Good Feelings, which coincided with James Monroe's presidency, there was a significant focus on measures to foster economic growth within the United States and protect American interests. The doctrine was implemented in 1823 and designed to deter European nations from political intervention in the Americas, supporting the independence of the emerging republics and ensuring a more secure environment for American commerce and territorial expansion.