"The World and Japan" Database (Project Leader: TANAKA Akihiko)
Database of Japanese Politics and International Relations
National Graduate Institute for Policy Studies (GRIPS); Institute for Advanced Studies on Asia (IASA), The University of Tokyo

[Title] Inter-American Treaty of Reciprocal Assistance (Rio Treaty)

[Date] September 2, 1947
[Source] Modern International Relations: Basic Documents, Volume 1, Kajima Institute of International Peace, pp.861-867.
[Notes] Signed: 2 September 1947
[Full text]

In the name of their Peoples, the Governments represented at the Inter-American Conference for the Maintenance of Continental Peace and Security, desirous of consolidating and strengthening their relations of friendship and good neighborliness, and


That Resolution 8 of the Inter-American Conference on Problems of War and Peace, which met in Mexico City, recommended the conclusion of a treaty to prevent and repel threats and acts of aggression against any of the countries of America:

That the High Contracting Parties reiterate their will to remain united in an inter-American system consistent with the purposes and principles of the United Nations, and reaffirm the existence of the agreement which they have concluded concerning those matters relating to the maintenance of international peace and security which are appropriate for regional action:

That the High Contracting Parties reaffirm their adherence to the principles of Inter-American solidarity and cooperation, and especially to those set forth in the preamble and declarations of the Act of Chapultepec, all of which should be understood to be accepted as standards of their mutual relations and as the juridical basis of the Inter-American System:

That the American States propose, in order to improve the procedures for the pacific settlement of their controversies, to conclude the treaty concerning the "Inter-American Peace System" envisaged in Resolutions 9 and 39 of the Inter-American Conference on Problems of War and Peace:

That the obligation of mutual assistance and common defense of the American Republics is essentially related to their democratic ideals and to their will to cooperate permanently in the fulfillment of the principles and purposes of a policy of peace:

That the American regional community affirms as a manifest truth that juridical organization is a necessary prerequisite of security and peace, and that peace is founded on justice and moral order and, consequently, on the international recognition and protection of human rights and freedoms, on the indispensable well-being of the people, and on the effectiveness of democracy for the international realization of justice and security,

Have resolved, in conformity with the objectives stated above, to conclude the following Treaty, in order to assure peace, through adequate means, to provide for effective reciprocal assistance to meet armed attacks against any American State, and in order to deal with threats of aggression against any of them:

Article 1 The High Contracting Parties formally condemn war and undertake in their international relations not to resort to the threat or the use of force in any manner inconsistent with the provisions of the Charter of the United Nations or of this Treaty.

Article 2 As a consequence of the principle set forth in the preceding Article, the High Contracting Parties undertake to submit every controversy which may arise between them to methods of peaceful settlement and to endeavor to settle any such controversy among themselves by means of the procedures in force in the Inter-American System before referring it to the General Assembly or the Security Council of the United Nations.

Article 3 1. The High Contracting Parties agree that an armed attack by any State against an American State shall be considered as an attack against all the American States and, consequently, each one of the said

Contracting Parties undertakes to assist in meeting the attack in the exercise of the inherent right of individual or collective self-defense recognized by Article 51 of the Charter of the United Nations.

2. On the request of the State or States directly attacked and until the decision of the Organ of Consultation of the Inter-American System, each one of the Contracting Parties may determine the immediate measures which it may individually take in fulfillment of the obligation contained in the preceding paragraph and in accordance with the principle of continental solidarity. The Organ of Consultation shall meet without delay for the purpose of examining those measures and agreeing upon the measures of a collective character that should be taken.

3. The provisions of this Article shall be applied in case of any armed attack which takes place within the region described in Article 4 or within the territory of an American State. When the attack takes place outside of the said areas, the provisions of Article 6 shall be applied.

4. Measures of self-defense provided for under this Article may be taken until the Security Council of the United Nations has taken the measures necessary to maintain international peace and security.

Article 4 (...)

Article 5 The High Contracting Parties shall immediately send to the Security Council of the United Nations, in conformity with Articles 51 and 54 of the Charter of the United Nations, complete information concerning the activities undertaken or in contemplation in the exercise of the right of self-defense or for the purpose of maintaining inter-American peace and security.

Article 6 If the inviolability or the integrity of the territory or the sovereignty or political independence of any American State should be affected by an aggression which is not an armed attack or by an extra-continental or intra-continental conflict, or by any other fact or situation might endanger the peace of America, the Organ of Consultation shall meet immediately in order to agree on the measures which must be taken in case of aggression to assist the victim of the aggression or, in any case, the measures which should be taken for the common defense and for the maintenance of the peace and security of the Continent.

Article 7 In the case of a conflict between two or more American States, without prejudice to the right of self-defense in conformity with Article 51 of the Charter of the United Nations, the High Contracting Parties, meeting in consultation shall call upon the contending States to suspend hostilities and restore matters to the statu quo ante bellum, and shall take in addition all other necessary measures to reestablish or maintain inter-American peace and security and for the solution of the conflict by peaceful means. The rejection of the pacifying action will be considered in the determination of the aggressor and in the application of the measures which the consultative meeting may agree upon.

Article 8 For the purposes of this Treaty, the measures on which the Organ of Consultation may agree will comprise one or more of the following: recall of chiefs of diplomatic missions; breaking of diplomatic relations; breaking of consular relations; partial or complete interruption of economic relations or of rail, sea, air, postal, telegraphic, telephonic, and radiotelephonic or radiotelegraphic communications; and use of armed force.

Article 9 In addition to other acts which the Organ of Consultation may characterize as aggression, the following shall be considered as such:

(a) Unprovoked armed attack by a State against the territory, the people, or the land, sea or air forces of another State;

(b) Invasion, by the armed forces of a State, of the territory of an American State, through the trespassing of boundaries demarcated in accordance with a treaty, judicial decision, or arbitral award, or, in the absence of frontiers thus demarcated, invasion affecting a region which is under the effective jurisdiction of another State.

Article 10 None of the provisions of this Treaty shall be construed as impairing the rights and obligations of the High Contracting Parties under the Charter of the United Nations.

Article 11 The consultations to which this Treaty refers shall be carried out by means of the Meetings of Ministers of Foreign Affairs of the American Republics which have ratified the Treaty, or in the manner or by the organ which in the future may be agreed upon.

Article 12 (...)

Article 13 The consultations shall be initiated at the request addressed to the Governing Board of the Pan American Union by any of the Signatory States which has ratified the Treaty.

Article 14 In the voting referred to in this Treaty only the representatives of the Signatory States which have ratified the Treaty may take part.

Article 15 The Governing Board of the Pan American Union shall act in all matters concerning this Treaty as an organ of liaison among the Signatory States which have ratified this Treaty between these States and the United Nations.

Article 16 The decisions of the Governing Board of the Pan American Union referred to in Articles 13 and 15 above shall be taken by an absolute majority of the Members entitled to vote.

Article 17 The Organ of Consultation shall take its decisions by a vote of two-thirds of the Signatory States which have ratified the Treaty

Article 18-Article 26 (...)