"San Salvador is closer to Houston, Texas, than Houston is to Washington, D.C. Central America is America and it's at our doorstep, and it has become a stage for a bold attempt, by the Soviet Union, Cuba and Nicaragua to install communism by force throughout the hemisphere." These simple words were spoken by President Reagan to defend U.S. intervention in Central America during the 1980s. Can it all have been so simple? Not quite. The underlying theme behind justifications for intervention was the Monroe Doctrine, the illustrious policy undertaken by the United States in which it treated intervention in the western hemisphere by foreign powers as a threat to national security. This work examines the history of the Doctrine and the legality of the interventions under domestic and international law. As world politics continues to charge ahead into the twenty-first century, we cannot help but wonder: will the Monroe Doctrine be dusted off by some future administration as a pretext for unilateral action in the western hemisphere once again? The answer lies in a close examination of the Doctrine itself.