GENERAL PRINCIPLES OF TREATY LAW

1. Definition and Nature of Treaties

A treaty is a formal agreement between two or more sovereign states or international organizations, governed by international law, and creating enforceable legal rights and obligations. Treaties can also be concluded between states and international organizations or between international organizations themselves.

In the Philippines, treaties are recognized as part of the law of the land, and adherence to treaty obligations is constitutionally mandated (Article II, Section 2 of the 1987 Constitution).

2. Sources of Treaty Law

The Vienna Convention on the Law of Treaties (VCLT) of 1969 is the principal instrument that codifies the rules on treaties. It reflects both customary international law and codified principles applicable to treaties. The Philippines is a signatory to the VCLT, and its provisions are considered binding.

The VCLT defines a treaty as "an international agreement concluded between States in written form and governed by international law."

3. Types of Treaties

Bilateral Treaties: Treaties between two parties (usually two states).
Multilateral Treaties: Treaties involving three or more states.
Plurilateral Treaties: A treaty between a limited number of states, often within a specific region or on specific issues.

4. Formation and Conclusion of Treaties

The formation of a treaty generally follows these stages:

Negotiation: States or their representatives negotiate the terms of the agreement.
Adoption of the Text: Once the states agree on the terms, the treaty text is adopted.
Signature: The treaty is signed by the authorized representatives of the states. The signature signifies the intent to be bound but does not yet create legal obligations unless the treaty provides otherwise.
Ratification: In most cases, states must ratify treaties according to their domestic constitutional processes. In the Philippines, Article VII, Section 21 of the 1987 Constitution requires the Senate's concurrence by a two-thirds vote for a treaty to be valid and binding.
Accession: A state that did not participate in the original negotiation and signing of a treaty may later become a party by acceding to it, if allowed by the treaty provisions.
Entry into Force: A treaty enters into force once the conditions specified within the treaty (often ratification by a certain number of states) are met.

5. Binding Force and Pacta Sunt Servanda

The principle of pacta sunt servanda (agreements must be kept) is the foundation of treaty law. Article 26 of the VCLT reflects this principle, requiring states to perform their treaty obligations in good faith. This binding nature applies unless a treaty is invalidated or terminated under recognized exceptions.

6. Interpretation of Treaties

Articles 31 to 33 of the VCLT provide rules on the interpretation of treaties:

Ordinary Meaning: Treaties must be interpreted according to the ordinary meaning of their terms in context and in light of the treaty’s object and purpose.
Context: The context includes the text, preamble, annexes, and any subsequent agreements or practices.
Supplementary Means: If the meaning remains ambiguous, preparatory work (travaux préparatoires) and circumstances of conclusion may be used as supplementary means of interpretation.

7. Invalidity of Treaties

A treaty may be considered void or voidable on the following grounds under Articles 46 to 53 of the VCLT:

Manifest Violation of Internal Law: If the consent of a state was given in violation of a fundamental rule of internal law.
Error: If a state entered into a treaty under a fundamental error regarding a fact or situation.
Fraud or Corruption: If a treaty was induced by fraudulent behavior or corruption.
Coercion: If consent was obtained through coercion of the state’s representative or the threat of force.
Conflict with Jus Cogens: A treaty is void if it conflicts with a peremptory norm (jus cogens), which is a fundamental principle of international law accepted by the international community (e.g., prohibitions on genocide, slavery, or torture).

8. Termination and Suspension of Treaties

The termination or suspension of treaties can occur through several mechanisms:

By Agreement: Parties can mutually agree to terminate or modify a treaty.
Breach: A material breach by one party may allow the other to terminate or suspend the treaty under Article 60 of the VCLT.
Impossibility of Performance: If the object of the treaty has disappeared or is destroyed, making performance impossible (Article 61 of the VCLT).
Fundamental Change of Circumstances (Rebus Sic Stantibus): If unforeseen changes fundamentally alter the basis on which the treaty was concluded, parties may invoke this doctrine to terminate or modify the treaty under Article 62 of the VCLT. However, the change must not be the result of the party's own actions.
Withdrawal or Denunciation: If the treaty provides for withdrawal or if the parties agree to allow withdrawal or denunciation.
Supervening Jus Cogens Norm: If a new peremptory norm of international law arises, conflicting treaties are void.

9. Effects of Treaties on Third States

Article 34 of the VCLT establishes the principle that a treaty does not create rights or obligations for third states without their consent, known as the principle of pacta tertiis nec nocent nec prosunt. However, third states may derive benefits from a treaty if it expressly provides for this possibility.

10. Reservations to Treaties

A reservation is a unilateral statement made by a state when signing, ratifying, accepting, or acceding to a treaty, whereby it seeks to exclude or modify the legal effect of certain provisions of the treaty.

Under Articles 19 to 23 of the VCLT, reservations are allowed unless:

The treaty prohibits reservations.
The reservation is incompatible with the object and purpose of the treaty.

States may accept or object to reservations made by other states.

11. Amendment and Modification of Treaties

Amendment: Formal changes to the treaty's provisions, often requiring the consent of all parties.
Modification: Bilateral or multilateral modification of treaty provisions between certain parties, usually through a separate agreement.

12. Domestic Application of Treaties in the Philippines

In the Philippines, treaties must undergo the process of ratification with Senate concurrence under Article VII, Section 21 of the 1987 Constitution. Once ratified, treaties form part of the national legal system.

Treaty vs. Executive Agreement: An executive agreement is a less formal type of international agreement that does not require Senate ratification. Executive agreements are still binding but are typically used for matters that do not alter national policy or require legislative approval.

The Supreme Court of the Philippines has consistently ruled that treaties and executive agreements have the same legal status as statutes. In case of conflict between a treaty and a domestic statute, courts will attempt harmonization, but treaties are generally presumed to take precedence.

13. State Responsibility for Breach of Treaties

States that violate their treaty obligations may incur state responsibility under international law, resulting in potential consequences such as diplomatic protests, sanctions, or even countermeasures by the aggrieved parties. Under customary international law, the breach of a treaty entitles the other parties to seek reparation or recourse to international dispute resolution mechanisms.

14. Dispute Settlement in Treaty Law

Many treaties include dispute settlement provisions, such as negotiation, arbitration, or judicial settlement. Absent specific provisions, disputes may be resolved through the International Court of Justice (ICJ), arbitration, or other peaceful means. The VCLT also provides mechanisms for dispute resolution regarding treaty interpretation or application under Article 66.

Conclusion

Treaty law is a complex but essential component of both public international law and the domestic legal framework of states. The Vienna Convention on the Law of Treaties forms the backbone of modern treaty law, codifying principles such as pacta sunt servanda, interpretation, and the regulation of treaty formation, modification, and termination. In the Philippines, treaties are part of the law of the land and must comply with constitutional requirements for ratification, ensuring that treaty obligations are honored in good faith.