The Inter-American Treaty of Reciprocal Assistance (commonly known as the Rio Treaty, the Rio Pact, the Treaty of Reciprocal Assistance, or by the Spanish-language acronym TIAR from Tratado Interamericano de Asistencia Recíproca) is an agreement signed in 1947 in Rio de Janeiro among many countries of the Americas. The central principle contained in its articles is that an attack against one is to be considered an attack against them all; this was known as the "hemispheric defense" doctrine. Despite this, several members have breached the treaty on multiple occasions. The treaty was initially created in 1947 and came into force in 1948, in accordance with Article 22 of the treaty. The Bahamas was the most recent country to sign and ratify it in 1982.