The Monroe Doctrine, a U.S. foreign policy initiative introduced in 1823, stated that efforts by European countries to colonise or interfere with states in the Americas will be viewed as acts of aggression requiring U.S. intervention, while the U.S. promised to refrain from interfering the affairs of established European colonies and respect the control of the European nations over their Caribbean colonies. Its justification was to make the "New World" safe for liberty and American-style republicanism, although many Latin Americans viewed the doctrine as simply justification for the United States to establish imperialistic relations with Latin America without having to worry about European interference. The Monroe Doctrine was invoked during the Second French intervention in Mexico and with the German Empire during the Zimmermann Telegram affair in 1917. After 1960 the Monroe Doctrine was invoked to roll back Communism from its new base in Castro's Cuba. Ronald Reagan emphasized the need to roll back Communism in Nicaragua and Grenada.