Law of treaties: conclusion, reservations, validity and termination

1. Definition and kinds

Article 2(1)(a) VCLT: 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. The name does not matter: convention, covenant, charter, protocol, pact, agreement, exchange of notes. Oral agreements and agreements involving international organisations are treaties under general international law, though outside the 1969 Convention (Article 3; the 1986 Vienna Convention covers organisations).

Kinds: bilateral and multilateral; law-making and treaty-contracts (see the note on sources); and, by subject, political, commercial, boundary, extradition, human rights treaties. Only States have full capacity to conclude treaties (Article 6).

2. Stages in the conclusion of a treaty

(1) Accrediting of persons: full powers. A person represents a State for adopting or authenticating a treaty or expressing consent if he produces appropriate full powers (Article 7(1)). Heads of State, heads of government and foreign ministers need none for any act; heads of diplomatic missions need none for adopting a treaty with the receiving State; representatives to a conference or organisation need none for adopting a text there (Article 7(2)). An act by an unauthorised person has no legal effect unless confirmed (Article 8).

(2) Negotiation. The representatives discuss and settle the terms, in bilateral talks or at a conference.

(3) Adoption of the text (Article 9): by the consent of all the participating States, or, at an international conference, by a two-thirds majority of those present and voting unless they decide otherwise by the same majority.

(4) Authentication (Article 10): the text is established as authentic and definitive by the procedure agreed or, failing that, by signature, signature ad referendum or initialling. After authentication the text cannot be altered except by agreement.

(5) Expression of consent to be bound (Article 11): by signature, exchange of instruments, ratification, acceptance, approval or accession, or any other agreed means.

• Signature (Article 12) binds where the treaty provides, or the parties so intend. Where signature is subject to ratification, it does not bind, but the signatory must refrain from acts which would defeat the object and purpose of the treaty until it has made clear its intention not to become a party (Article 18).
• Ratification (Article 14): approval by the competent authority of the State (in India, the Union executive) after signature. Its purposes: to allow time for second thoughts, for domestic legislation, and for parliamentary consultation where a constitution requires it. There is no obligation to ratify a signed treaty.
• Accession (Article 15): by a State that did not sign, where the treaty permits it. Acceptance and approval are used like ratification.

(6) Exchange or deposit of instruments (Article 16): instruments of ratification are exchanged (bilateral) or deposited with the depositary, often the UN Secretary-General (multilateral).

(7) Reservations, if any (section 3 below).

(8) Entry into force (Article 24): as the treaty provides (often after a set number of ratifications, for example sixty for UNCLOS), or, failing that, when all negotiating States have consented. A treaty does not apply to acts before its entry into force (Article 28).

(9) Registration and publication: every treaty entered into by a UN member shall be registered with the Secretariat and published (Charter, Article 102(1)). An unregistered treaty cannot be invoked before any organ of the UN (Article 102(2)), though it remains valid between the parties. VCLT Article 80 is to the same effect.

(10) Application and execution: incorporation into municipal law where required.

3. Reservations

A reservation is a unilateral statement, however phrased or named, made by a State when signing, ratifying, accepting, approving or acceding, by which it purports to exclude or modify the legal effect of certain provisions in their application to that State (Article 2(1)(d)). It must be distinguished from an interpretative declaration, which only explains the State's understanding.

• The older rule required the consent of all parties to a reservation (the League practice).
• Reservations to the Genocide Convention, ICJ advisory opinion, 1951: a State making a reservation objected to by some parties but not others can be regarded as a party if the reservation is compatible with the object and purpose of the Convention. Each party decides for itself.
• Article 19: a reservation may be made unless (a) it is prohibited by the treaty, (b) the treaty permits only specified reservations, or (c) it is incompatible with the object and purpose.
• Article 20: a reservation expressly authorised needs no acceptance; for plurilateral treaties, acceptance by all is needed; for constituent instruments of organisations, acceptance by the competent organ. Otherwise acceptance by one party makes the reserving State a party in relation to that party; objection does not prevent the treaty entering into force between them unless the objecting State so states. A reservation is treated as accepted if no objection is raised within twelve months (Article 20(5)).
• Article 21: the reservation modifies the provisions between the reserving State and the accepting State in both directions; where an objecting State does not oppose entry into force, the provisions to which the reservation relates do not apply between the two to the extent of the reservation.

4. Observance and interpretation

• Pacta sunt servanda (Article 26): every treaty in force is binding upon the parties and must be performed by them in good faith.
• Internal law is no justification for non-performance (Article 27), subject to Article 46.
• Interpretation (Article 31): in good faith, in accordance with the ordinary meaning of the terms in their context and in the light of the treaty's object and purpose, taking account of later agreements and practice. Supplementary means (Article 32), including the preparatory work (travaux préparatoires), are used to confirm the meaning or where it is ambiguous or absurd.
• Third States (Article 34): a treaty does not create obligations or rights for a third State without its consent.

5. Invalidity

Grounds (Articles 46 to 53): manifest violation of internal law on competence to conclude treaties, of fundamental importance (46); a representative exceeding a specific restriction on authority that was notified (47); error of fact forming an essential basis of consent (48), but not if the State contributed to it (Temple of Preah Vihear); fraud (49); corruption of a representative (50); coercion of a representative (51); coercion of a State by threat or use of force in violation of the Charter (52); and conflict with a peremptory norm (jus cogens), which makes the treaty void (53). A treaty conflicting with a new peremptory norm becomes void (64).

6. Termination and suspension

• By the treaty's own provisions or by consent of all parties (Article 54): expiry of a fixed term, a resolutory condition, or a later treaty on the same subject (Article 59).
• Denunciation or withdrawal where the treaty has no termination clause is not allowed unless the parties intended it or a right is implied by the nature of the treaty; twelve months' notice is required (Article 56).
• Material breach (Article 60): a repudiation not sanctioned by the Convention, or violation of a provision essential to the object or purpose. The other party to a bilateral treaty may terminate or suspend it; for multilateral treaties the rules are more restrictive. Does not apply to humanitarian provisions protecting persons (Article 60(5)). Namibia advisory opinion (ICJ, 1971): South Africa's material breach justified the General Assembly's termination of the mandate.
• Supervening impossibility (Article 61): permanent disappearance or destruction of an object indispensable for execution, such as the submergence of an island.
• Fundamental change of circumstances, rebus sic stantibus (Article 62): may be invoked only if the circumstances constituted an essential basis of consent and the change radically transforms the obligations still to be performed. It cannot be invoked for a boundary treaty, or where the change results from the invoking party's own breach. It was rejected in Fisheries Jurisdiction (UK v. Iceland), ICJ, 1973, and in Gabčíkovo-Nagymaros, ICJ, 1997.
• Severance of diplomatic relations does not affect treaty relations unless the relations are indispensable to application (Article 63).
• Outbreak of war: political treaties end, but humanitarian treaties and treaties intended to apply in war continue (ILC Articles on the Effects of Armed Conflicts on Treaties, 2011).

7. India's treaty practice

Treaty-making is an executive act under Article 73 read with Entry 14 of List I; Parliament may legislate to implement any treaty under Article 253. In Union of India v. Azadi Bachao Andolan, 2003 INSC 526, (2004) 10 SCC 1, upholding a circular under the India-Mauritius Double Taxation Avoidance Convention, the Court affirmed that the power to enter into treaties is an executive power and that a treaty made under section 90 of the Income-tax Act, 1961 (that Act was replaced from 1 April 2026 by the Income-tax Act, 2025, which carries a corresponding power to enter into tax treaties) operates even where it departs from the general provisions of the Act. A treaty affecting the rights of citizens or changing the law needs legislation (Maganbhai Ishwarbhai Patel v. Union of India, 1969 INSC 4, (1970) 3 SCC 400), and one ceding territory needs a constitutional amendment (In re Berubari Union, 1960 INSC 49, AIR 1960 SC 845).

How this is examined

For “stages in the conclusion of treaties”, write the ten stages in order with their Articles; that alone fills a ten-mark answer. For “formation and termination”, compress the stages into a paragraph, then give the grounds of invalidity briefly and the modes of termination in full, with rebus sic stantibus and the two cases. A short note on reservations should give the Article 2(1)(d) definition, the Genocide opinion, and Articles 19 to 21.