The Monroe Doctrine is the best known U.S. policy toward the Western Hemisphere. Buried in a routine annual message delivered to Congress by President James Monroe in December 1823, the doctrine warns European nations that the United States would not tolerate further colonization or puppet monarchs.
Well, to start, the Supreme Court could have ruled differently in Plessy v. Ferguson.
In Plessy, the Supreme Court condoned the practice of "separate but equal" making it permissible for the white south (and north) to create discriminatory practices.
