Wickipedia:

"The Cold War
During the Cold War, the Monroe doctrine was applied to Latin America by the framers of U.S. foreign policy. When the Cuban Revolution established a socialist regime with ties to the Soviet Union, after trying to establish fruitful relations with the U.S., it was argued that the spirit of the Monroe Doctrine should be again invoked, this time to prevent the further spreading of Soviet-backed Communism in Latin America. During the Cold War, the United States thus often provided intelligence and military aid to Latin and South American governments that claimed or appeared to be threatened by Communist subversion. This, in turn, led to some domestic controversy within the United States, especially among some members of the left who argued that the Communist threat and Soviet influence in Latin America was greatly exaggerated. (See Operation PBSUCCESS.)"

"The debate over this new spirit of the Monroe Doctrine came to a head in the 1980s, as part of the Iran-Contra Affair. Among other things, it was revealed that the U.S. Central Intelligence Agency had been covertly training "Contra" guerrilla soldiers in Nicaragua in an attempt to destabilize the country and overthrow the Sandinista revolutionary government and its President, Daniel Ortega. CIA director Robert Gates vigorously defended the Contra operation, arguing that avoiding U.S. intervention in Nicaragua would be "totally to abandon the Monroe doctrine". In a case brought before the International Court of Justice by Nicaragua, however, the court ruled that the United States had exercised "unlawful use of force." The U.S. ignored the verdict. The Carter and Reagan administrations embroiled themselves in the civil war in El Salvador, again citing the Monroe Doctrine as justification. The conflict was marked by large scale human rights abuses and the 1980 assassination of Archbishop Oscar Arnulfo Romero by right-wing death squads. The Monroe Doctrine was also cited during the U.S. intervension in Guatemala and the invasion of Grenada. Critics of the Reagan administration's support for Britain in the Falklands War charge that the U.S. ignored the Monroe Doctrine in that instance".

It would seem the Monroe Doctrine is used in to justify legally or illlegally what ever action we might at any time wish to perceive it needs to embrace. Legitimate IMO only in respect to the position that "might makes right' !