U.S. invasions and interventions don't seem to bother the OAS too much.
In 1973, during the coup against leftist President Salvador Allende, the Organization of American States stayed silent, even after the death of the president. With the support of the United States, General Augusto Pinochet took power, while the OAS applauded the move. In fact, in 1976 the VI Summit of the OAS was held in Pinochet's Chile. At that meeting, U.S. Secretary of State Henry Kissinger gave a speech on human rights and told Pinochet, "We want your government to be a prosperous government. We want to help you and not obstruct your work." The brutal dictatorship led to the murder, torture and forced disappearance of thousands of Chileans
2. Dominican Republic
The U.S. invasion of the Dominican Republic in 1965 represented the institutionalized intervention of the OAS with the Inter-American Peace Force. Before the invasion, the OAS sent its Secretary General Jose A. Mora from Uruguay presumably to lay the groundwork for the invasion with the excuse of seeking a truce between the opposing parties. The U.S. invaded and led a tank attack for more than 48 hours to counter the victory of the leftist Popular Constitutionalist Movement.
President Jacobo Arbenz, who promoted agrarian reform in Guatemala, was overthrown in a U.S. invasion in 1954. Before the invasion, the OAS passed a resolution allowing "regional collective intervention," in violation of its initial rules. The agency did not question the actions of the United States and instead backed the military dictatorship of Carlos Castillo Armas. Declassified documents revealed that the coup in Guatemala was the result of a covert CIA operation.
With the triumph of the Cuban Revolution, the OAS simply did not think that "Marxism-Leninism" was compatible with its principles. In 1962 Cuba was finally expelled from the OAS, after a series of diplomatic actions aimed at isolating the island nation. The OAS devoted itself to drafting reports of alleged human rights violations in Cuba but said nothing of the U.S. Bay of Pigs invasion of 1961 and has remained silent about the economic, financial and commercial blockade imposed by the United States.
The United States bombed and invaded Panama in 1989. President Manuel Noriega was kidnapped, made to stand trial in the U.S., and sentenced to 40 years in prison. Although the invasion was obviously illegal and in violation of the OAS charter, the agency "condemned" the facts superfluously and took no action.