Outside of the Warsaw Pact, Cuba embraced its own aggressive theory of proletarian internationalism, which was primarily exercised through support for leftist revolutionary movements. One of the fundamental aspects of Cuban foreign policy between 1962 and 1990 was the "rule of internationalism", which dictated that Cuba must first and foremost support the cause of international revolution through whatever means are available to her. At the founding of the Organization of Solidarity with the People of Asia, Africa and Latin America in 1966, Cuban President Fidel Castro declared that "for Cuban revolutionaries, the battleground against imperialism encompasses the entire world...the enemy is one and the same, the same one who attacks our shores and our territory, the same one who attacks everyone else. And so we say and proclaim that the revolutionary movement in every corner of the world can count on Cuban combat fighters". By the mid 1980s, it was estimated that up to a quarter of Cuba's national military was deployed overseas, fighting with communist governments or factions in various civil conflicts. The Cuban military saw action against the United States while fighting on behalf of the Marxist New Jewel Movement in Grenada. It was also instrumental in installing a communist government in Angola and fighting several costly campaigns during that nation's civil war.