The treaty was invoked numerous times during the 1950s and 1960s , in particular supporting the United States ' naval blockade unanimously during the Cuban Missile Crisis . With the exceptions of Trinidad and Tobago ( 1967 ) and the Bahamas ( 1982 ) , no countries that became independent after 1947 have joined the treaty ; Canada is yet to become a member , though it already has separate defense commitments with the US . During the Falklands War , the United States favored the United Kingdom because Argentina had been the agressor , and because Argentina had not been attacked , as did Chile and Colombia . This was seen by most Latin American countries as the final failure of the treaty . In 2001 , the United States invoked the Rio Treaty after the September 11 attacks . In September 2002 , citing the Falklands example and anticipating the Iraq War , Mexico formally withdrew from the treaty ; after the requisite two years , Mexico ceased to be a signatory in September 2004
September 11 attacks
September 11 attacks
Inter-American Treaty of Reciprocal Assistance