Following the September 11 attacks of 2001 , Brazil was the first to propose invocation of the Inter-American Treaty of Reciprocal Assistance , also known as the Rio Treaty , which stipulates that " an armed attack on one member is to be considered an attack on all . " The treaty was activated September 19 in a meeting of Western Hemisphere foreign ministers at the Organization of American States . On October 1 , President Cardoso stated that the United States had not requested Brazilian military support and that Brazil does not intend to offer any . Despite Brazil 's initial support for the United States , it did not opt to actively join the War on Terror and under President Lula , it strongly opposed the Bush administration 's Iraq War
September 11 attacks
September 11 attacks
Brazil–United States relations