Law of Treaties

About this topic

The law of treaties decides whether an agreement between States is a treaty, how it is made, whom it binds and on what terms, whether it is valid, and when it ends. Three imaginary problems show the kind of questions it answers.

The five questions

Any treaty problem can be solved by asking five questions in this order:

1. Is it a treaty at all?
2. Was it made properly?
3. Whom does it bind, and on what terms?
4. Is it valid?
5. Is it still alive?

The Vienna Convention on the Law of Treaties, 1969

The basic rulebook of the law of treaties is the Vienna Convention on the Law of Treaties, 1969 (VCLT).

• It entered into force on 27 January 1980.
• It has a preamble, eight parts, 85 articles and an annex.
• India has not joined it. However, the Supreme Court of India accepts that many of its rules reflect customary international law, which binds every State.

Question 1: Is it a treaty at all?

Definition: Article 2

A treaty is "an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation."

Essentials of a treaty

The definition can be read as a checklist:

1. Written form: the agreement must be in writing.
2. Between States: the parties must be States.
3. Governed by international law: the parties must have intended to create legal rights and duties under international law. A mere political promise, or a contract under some national law, is not a treaty.
4. Form and label do not matter: the treaty may be in a single instrument or in two or more related instruments, and its name is irrelevant.

A treaty may therefore be called a convention, covenant, pact, charter, protocol, agreement or exchange of notes. A protocol is often a later instrument that adds to or amends an earlier treaty.

Scope of the Convention: Article 1

• Under Article 1, the VCLT 1969 covers only treaties between States.
• International organisations, such as the United Nations (UN), also make treaties. A separate Vienna Convention of 1986 was drawn up for them.
• Historically, even entities with limited sovereignty, such as protectorates, concluded treaties within the capacity allowed to them.

Kinds of treaties

Treaties fall into two families.

Question 2: Was it made properly? Conclusion of treaties

The making of a treaty can be remembered as a chain of six links: Talk, Text, Sign, Seal, Start, Shelf.

Talk: authority to represent the State (Article 7)

Negotiation needs an authorised speaker, normally one carrying full powers: a formal document from the competent authority of the State, like a power of attorney for a nation.

Under Article 7, three groups need no such document:

1. Heads of State, Heads of Government and Ministers for Foreign Affairs may perform all acts relating to the conclusion of a treaty.
2. Heads of diplomatic missions may adopt the text of a treaty between their State and the State where they are posted.
3. Representatives accredited to an international conference or organisation may adopt a text there.

Text: adoption of the text (Article 9)

• General rule: adoption needs the consent of all the States drawing up the treaty.
• At an international conference: the vote of two-thirds of the States present and voting, unless the same majority decides to apply a different rule.

Sign: signature (Article 12)

Signature may only confirm that the text is authentic, or it may also bind the State. Under Article 12, signature expresses consent to be bound when:

1. the treaty says so;
2. it is otherwise established that the negotiating States agreed that signature should have that effect; or
3. the State's intention to give signature that effect appears from its representative's full powers or was expressed during the negotiation.

Seal: final consent to be bound

Meaning (Article 2)

Ratification, acceptance, approval and accession each mean "the international act so named whereby a State establishes on the international plane its consent to be bound by a treaty."

Who gives the seal: treaty-making power in India

Who gives the final consent is decided by each State's own law.

• In India, treaty-making is part of the executive power of the Union. This power vests in the President and is exercised on the aid and advice of the Council of Ministers.
• So the Union Cabinet decides, and the Constitution does not require Parliament's approval before ratification.
• Implementation is a separate matter, governed by Article 253 of the Constitution.

Article 253: "Notwithstanding anything in the foregoing provisions of this Chapter, Parliament has power to make any law for the whole or any part of the territory of India for implementing any treaty, agreement or convention with any other country or countries or any decision made at any international conference, association or other body."

Ratification is a free choice; the interim duty (Article 18)

A signatory has no legal duty to ratify and owes nobody reasons. But under Article 18, a State must refrain from acts which would defeat the object and purpose of a treaty:

• when it has signed the treaty, or exchanged instruments, subject to ratification, acceptance or approval, until it makes clear that it will not become a party; and
• when it has consented to be bound and the treaty awaits entry into force, provided entry into force is not unduly delayed.

Accession: the side door for latecomers (Article 15)

A State that did not take part earlier may join by accession when:

1. the treaty provides for it;
2. the negotiating States agreed to allow it; or
3. all the parties later agree.

Start: entry into force (Articles 24 and 28)

• Article 24: a treaty enters into force in the manner and on the date it provides or the negotiating States agree. Failing that, it enters into force once all the negotiating States have consented to be bound.
• Obligations then run forward, not from the day of signature.
• Article 28 (non-retroactivity): unless a different intention appears, a treaty does not bind a party for any act or fact which took place, or any situation which ceased to exist, before the treaty entered into force for that party.

Shelf: registration (Article 102, UN Charter)

• Every treaty and international agreement entered into by any Member after the Charter came into force must be registered with the UN Secretariat as soon as possible and published by it.
• An unregistered treaty stays valid, but no party may invoke it before any organ of the UN, including the ICJ.
• The purpose is simple: no secret deals.

Question 3: Whom does it bind? Pacta sunt servanda

The foundation of treaty obligation is pacta sunt servanda: promises between States must be honoured.

Article 26: "Every treaty in force is binding upon the parties to it and must be performed by them in good faith."

Good faith

Good faith blocks clever escapes where the words are obeyed but the purpose is defeated.

Internal law is no excuse (Article 27)

Article 27: "A party may not invoke the provisions of its internal law as justification for its failure to perform a treaty. This rule is without prejudice to article 46."

Change of government: Problem 1 solved

A treaty is concluded by the State, not by the person in office. A company's chief executive may change, but the company still owes its bank loan. Likewise, a new government, whether it comes by election, coup or revolution, inherits its State's treaties.

Change of State: succession of States

Things change only when the State itself changes. The rules are in the Vienna Convention on Succession of States in respect of Treaties, 1978.

• Article 16 (clean slate): a newly independent State, meaning a former dependent territory, "is not bound to maintain in force, or to become a party to, any treaty by reason only of the fact that at the date of the succession of States the treaty was in force in respect of the territory to which the succession of States relates."
• Article 11 (boundaries): a succession of States does not as such affect a boundary established by a treaty, or obligations and rights established by a treaty and relating to the regime of a boundary.
• Article 15 (part of a territory passes to another State): the old sovereign's treaties stop applying to that territory from the date of succession, and the new sovereign's treaties apply there, unless that would be incompatible with a treaty's object and purpose or would radically change the conditions for its operation.

On what terms? Reservations

Definition (Article 2)

A reservation is "a unilateral statement, however phrased or named, made by a State, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to that State."

When a reservation may be made (Article 19)

A State may formulate a reservation unless:

1. the treaty prohibits it;
2. the treaty allows only specified reservations, which do not include this one; or
3. in other cases, the reservation is incompatible with the object and purpose of the treaty.

Acceptance of reservations: special cases (Article 20)

• Expressly authorised reservation: needs no later acceptance unless the treaty says so.
• Small number of negotiating States: where the small number of negotiating States and the treaty's object and purpose show that the treaty must apply in its entirety between all, every party must accept the reservation.
• Treaty creating an international organisation: unless it provides otherwise, the reservation must be accepted by the competent organ of that organisation.

Effect of acceptance, objection and silence (Articles 20 and 21): Problem 2 solved

In other cases, unless the treaty provides otherwise, the following rules apply, using Westland's reservation to the ICJ dispute clause as the example.

• Westland's consent to be bound takes effect once at least one other contracting State accepts the reservation.
• The reservation never changes the treaty among the other parties themselves.

Treaties and third States

Two neighbours can agree to build a shared wall, but they cannot make a third neighbour pay for it. The maxim pacta tertiis nec nocent nec prosunt says treaties neither burden nor benefit third parties.

Article 34: "A treaty does not create either obligations or rights for a third State without its consent."

Three refinements

1. Obligations (Article 35): an obligation arises for a third State if the parties intend the provision to create it and the third State expressly accepts it in writing.
2. Rights (Article 36): a right arises for a third State, for a group of States to which it belongs, or for all States, if the parties intend it and the third State assents. Assent is presumed so long as the contrary is not indicated, unless the treaty provides otherwise. The right must be used on the conditions laid down for it.
3. Custom (Article 38): a treaty rule may still bind a third State as a customary rule of international law, recognised as such. This is the "league rulebook" (law-making treaty) at work: the outsider is bound by custom, not by the treaty.

Question 4: Is it valid? Invalidity of treaties

Validity can be checked like a doctor examining a newborn, with five checks:

1. Who signed? Authority (Articles 46 and 47)
2. What did they believe? Error (Article 48)
3. Did anyone cheat? Fraud and corruption (Articles 49 and 50)
4. Did anyone use force? Coercion (Articles 51 and 52)
5. What does it say? Conflict with jus cogens (Article 53)

Who signed: authority (Articles 46 and 47)

• Article 46: a State cannot call its consent invalid because it breached an internal rule on competence to conclude treaties, unless the violation was manifest and concerned a rule of fundamental importance.
• Manifest means objectively evident to any State conducting itself in the matter in accordance with normal practice and in good faith.
• Article 47: a specific restriction on a representative's authority counts only if it was notified to the other negotiating States before the representative expressed consent.

What they believed: error (Article 48)

• A State may invoke an error about a fact or situation which it assumed to exist when the treaty was concluded, and which formed an essential basis of its consent.
• It cannot do so if it contributed to the error by its own conduct, or if the circumstances put it on notice of a possible error.
• An error only in the wording of the text does not affect validity. It is corrected under Article 79.

Did anyone cheat: fraud and corruption (Articles 49 and 50)

• Fraud (Article 49): fraudulent conduct of another negotiating State.
• Corruption (Article 50): corruption of the State's representative, directly or indirectly, by another negotiating State.
• The victim State may invoke either ground.

Did anyone use force: coercion (Articles 51 and 52)

Force is treated more severely.

• Coercion of the representative (Article 51): consent procured by coercing the representative through acts or threats directed against that person is without any legal effect.
• Coercion of the State (Article 52): a treaty is void if procured by the threat or use of force in violation of the principles of international law embodied in the UN Charter.
• Economic and political pressure were left out of Article 52. The Vienna conference condemned them only in a separate declaration.

Relative and absolute invalidity (Article 45)

Authority, error, fraud and corruption hand the injured State a "key": it may choose to invoke the defect. Under Article 45, it loses that key if, after learning the facts, it expressly agrees that the treaty is valid, or by its conduct must be considered to have acquiesced. Coercion and jus cogens need no key, and no later acceptance cures them.

What does it say: conflict with jus cogens (Article 53)

Article 53: "A treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general international law. For the purposes of the present Convention, a peremptory norm of general international law is a norm accepted and recognized by the international community of States as a whole as a norm from which no derogation is permitted and which can be modified only by a subsequent norm of general international law having the same character."

Jus cogens norms are like the load-bearing pillars of a building. Tenants may rearrange the furniture by agreement, but no agreement can remove a pillar.

In 2022, the International Law Commission listed, without claiming that the list is complete, the following peremptory norms:

• prohibition of aggression;
• prohibition of genocide;
• prohibition of crimes against humanity;
• prohibition of racial discrimination and apartheid;
• prohibition of slavery;
• prohibition of torture;
• the basic rules of international humanitarian law (IHL);
• the right of self-determination.

Since the test is acceptance by the international community of States as a whole, new pillars can rise.

Question 5: Is it still alive? Termination and suspension

A treaty can end through three kinds of exits: planned, agreed and emergency.

Planned exits (Articles 54 and 56)

• Article 54: termination or withdrawal may take place in conformity with the treaty's own provisions.
• Article 56: if the treaty says nothing about termination, denunciation or withdrawal, a party cannot leave unless the parties intended to allow it, or a right to leave may be implied by the nature of the treaty. Even then, at least 12 months' notice is required.

Agreed exits (Articles 54 and 59)

• Article 54: termination or withdrawal may happen at any time by consent of all the parties, after consultation with the other contracting States.
• Article 59: a treaty ends if all its parties conclude a later treaty on the same subject matter, and either they intended the later treaty to govern, or the two treaties cannot be applied at the same time.
• If the parties intended only a pause, the earlier treaty is merely suspended.

Emergency exits

Emergency exits open when something goes wrong.

1. Material breach (Article 60)

A material breach means:

• a repudiation of the treaty not sanctioned by the Convention; or
• the violation of a provision essential to the accomplishment of the treaty's object or purpose.

Consequences:

• Bilateral treaty: the other party may terminate the treaty or suspend it in whole or in part.
• Multilateral treaty:
  • the other parties, by unanimous agreement, may suspend or terminate it, either in their relations with the defaulting State or as between all the parties;
  • a specially affected party may suspend it in its relations with the defaulter;
  • where the breach radically changes every party's position on further performance, any party except the defaulter may suspend it for itself.
• All this is without prejudice to the treaty's own provisions on breach.
• None of it applies to provisions protecting the human person in humanitarian treaties, especially those prohibiting reprisals against protected persons.

2. Supervening impossibility of performance (Article 61)

• Permanent disappearance or destruction of an object indispensable for the execution of the treaty allows termination or withdrawal.
• Temporary impossibility allows only suspension.
• No party may rely on an impossibility caused by its own breach of the treaty or of any other international obligation owed to another party.

3. Fundamental change of circumstances: rebus sic stantibus (Article 62)

Clausula rebus sic stantibus is the idea that a treaty assumes things stay as they were. It is the narrowest door. An unforeseen fundamental change of circumstances can be invoked only if:

1. those circumstances were an essential basis of the parties' consent; and
2. the change radically transforms the extent of obligations still to be performed.

It can never be invoked:

• for a treaty establishing a boundary; or
• if the change results from the invoking party's own breach of the treaty or of any other international obligation owed to another party.

Where the change can end a treaty, it can also be invoked merely to suspend it.

4. Emergence of a new peremptory norm (Articles 64 and 71)

Article 64: "If a new peremptory norm of general international law emerges, any existing treaty which is in conflict with that norm becomes void and terminates."

• Under Article 71, the parties are released from further performance.
• What was created by performing the treaty earlier survives only so far as keeping it does not itself conflict with the new norm.

Effect of armed conflict on treaties: Problem 3 solved

• Under Article 73, the VCLT does not prejudge questions arising from a succession of States, from the international responsibility of a State, or from the outbreak of hostilities between States.
• The older view was that war ended political treaties between enemies, such as alliances.
• Today, armed conflict does not automatically end or suspend treaties. It depends on their nature.
• The Geneva Conventions exist for war itself, and boundary treaties continue.

Quick revision

• Problem 1: Northland is bound, because governments change but States continue.
• Problem 2: Westland is inside the treaty, with a full, trimmed or no relationship depending on each partner's reply.
• Problem 3: The first shot did not automatically kill any treaty.
• Five questions: Is it a treaty at all? Was it made properly? Whom does it bind, and on what terms? Is it valid? Is it still alive?
• One chain of six links: Talk, Text, Sign, Seal, Start, Shelf.
• Three kinds of exits: planned, agreed and emergency.