Theories of the Basis of International Law

What is right about it

It explains obligations that consent cannot. It explains why genocide is unlawful for a State that never ratified the Genocide Convention. It supplies a standard for criticising the law rather than merely describing it, and it is where the moral energy of the human rights movement came from.

What is wrong with it

It cannot say what the rules are. Reason, appealed to by different people in different centuries, has produced opposite answers. Natural law was used to justify the colonisation it was also used to condemn, and doctrines of a natural hierarchy of civilisations were defended in the same vocabulary.

It has no way of settling a dispute. If two States both appeal to reason and disagree, nothing in the theory tells you which is right.

It makes the actual practice of States irrelevant, which is a strange result for a subject in which the practice of States is most of the evidence.

Positivism

What it says

The positivist school holds that international law is binding because States have consented to it. Law is not found, it is made, and it is made by the will of the States that are bound.

The evidence is the practice: treaties are agreements, and custom is a general practice accepted as law. Both look like consent.

Consent theory in its simple form says a State is bound only by what it has agreed to, expressly by treaty or tacitly by participating in the formation of a custom.

The auto-limitation theory, associated with Georg Jellinek, refines it. A sovereign State cannot be subjected to a will outside its own, so obligation must come from the State limiting itself. The State's own will, self-restricted, is the source of the obligation.

Bynkershoek and, in the nineteenth century, jurists such as Triepel and Anzilotti, developed the positivist account. Anzilotti built the whole system on pacta sunt servanda, meaning agreements must be kept, treated as an axiom that needs no further justification.

What is right about it

It matches how the subject actually works. Treaties are negotiated, signed and ratified; reservations are entered and objected to; States argue about whether they participated in a practice. All of that is the language of consent, and any theory that cannot account for it is describing some other subject.

It also matches the sources: article 38 of the Statute of the International Court of Justice lists conventions and custom first, and both are consent-based on their face.

What is wrong with it

New States. A State that became independent in 1960 was bound at once by the customary law of the sea, of diplomatic relations and of State responsibility, none of which it had participated in making. Pure consent theory has no comfortable answer, and the usual one, that the new State impliedly consents by entering the international community, is a fiction that does the work by assumption.

Jus cogens. Article 53 makes some norms non-derogable by agreement. If consent were the whole basis, States could agree to anything.

Auto-limitation is circular. If the State's own will is the source of obligation, the State can withdraw its will and end the obligation. A promise that binds only so long as the promisor wishes to be bound is not a promise. Anzilotti's answer, that pacta sunt servanda is an axiom outside the system, concedes that at least one rule is not consensual, which is exactly the naturalist's point.

Custom does not really need consent. The persistent objector rule, which the Fisheries case supports and which is set out in [Custom], allows a State to escape a new rule by objecting from the start. But a State that simply says nothing is bound, and silence is not consent in any ordinary sense.

The modern theories

Kelsen and the pure theory

Hans Kelsen tried to remove morality and politics from the account altogether. Every norm derives validity from a higher norm, and the chain must end somewhere, in a Grundnorm, a basic norm that is presupposed rather than derived.

For Kelsen the Grundnorm of the whole legal order is international, and he identified it either with pacta sunt servanda or with the principle that States ought to behave as they have customarily behaved. Municipal legal orders then derive their validity from international law, which is the strong monist position taken up in [International Law and Municipal Law].

The strength of this is its rigour. Its weakness is that a presupposed basic norm explains obligation only in the sense of naming the place where the explanation stops.

The sociological school

Leon Duguit and Georges Scelle held that law arises from the facts of social life. Human beings and communities are interdependent, that interdependence generates rules, and the State is not a mystical sovereign but a set of officials who happen to act. Scelle's dedoublement fonctionnel, or role splitting, describes how State officials act simultaneously as organs of their own State and as organs of the international community, because there are no separate international organs to do it.

This explains something the other theories struggle with: why the law grows fastest where interdependence is greatest, which is why aviation, posts, shipping, telecommunications, health and trade are its most developed fields.

The doctrine of fundamental rights

An older theory, still asked about, holds that States have certain fundamental rights inherent in statehood, usually listed as independence, equality, self-preservation and jurisdiction over their territory, and that international law is derived from these. It is closely tied to naturalism.

Its defect is that it is derived from a fiction. States are not people, and self-preservation as a legal right was used for a century to justify almost anything, until article 2(4) of the Charter and the narrow exception in article 51 replaced it with a rule.

The consent-plus-community view

Most working international lawyers today hold something less tidy than any of the above: that consent explains the great bulk of international law, that a narrow core of peremptory norms binds regardless of consent, and that the community interest expressed through the United Nations and through obligations owed to all States has grown at the expense of pure bilateralism.

That is not a compromise for want of nerve. It is what article 38 plus article 53 of the Vienna Convention actually amount to when read together.

The doctrines you must be able to state

Three phrases recur in this module and every one of them is a doctrine, not merely a maxim.

Pacta sunt servanda, agreements must be kept. Article 26 of the Vienna Convention on the Law of Treaties puts it in statutory form: every treaty in force is binding upon the parties to it and must be performed by them in good faith. It is worked in [Rights and Duties of the Parties, and Third States].

Jus cogens, a peremptory norm. Article 53: a norm accepted and recognised by the international community of States as a whole as one from which no derogation is permitted and which can be modified only by a subsequent norm of the same character. A treaty conflicting with one is void. It is worked in [Validity of Treaties, and Jus Cogens].

Rebus sic stantibus, things standing thus. The doctrine that a fundamental change of circumstances may allow a party to withdraw from a treaty. Article 62 of the Vienna Convention states it in a deliberately narrow form, and it is worked in [Termination and Suspension of Treaties].

Distinctions table

A worked example

State P has never ratified any human rights treaty and has never voted for any resolution on torture. Its officials torture a detainee, a national of State Q. State Q protests that State P has violated international law. State P replies that it has consented to no such rule.

On pure consent theory State P has an argument, and it is the argument that shows the theory's limits.

On naturalist theory State P is bound because the prohibition of torture is part of a higher law that consent cannot reach. The difficulty is that this proves too much and too easily; the same reasoning has been used to support propositions that were merely the speaker's convictions.

On the modern view State P is bound and the reasoning is legal rather than moral. The prohibition of torture is a rule of customary international law, established by the general practice of States accepted as law, and State P did not object to it as it formed. It is further a peremptory norm within article 53, so no State can contract out of it even by treaty. State P's consent is therefore not required, and the argument fails.

Notice that the modern answer used the positivist machinery of custom and then reached beyond it. That is exactly the hybrid position described above, and it is the answer to write.

What it does NOT mean

These are not rival descriptions of different subjects. They are rival explanations of the same rules, and a good answer treats them as competing accounts of one thing.

Positivism does not mean the law is whatever powerful States say. It means the law is what States have accepted as law, which is a different and much more constrained claim.

Naturalism is not the same as morality. A naturalist claims the higher law is legally binding, not merely that it ought to be followed. Confusing the two collapses the distinction the last chapter was built on.

A "theory" is not a source. Nobody wins a case by proving Kelsen right. The sources are in [The Sources of International Law], and they are the same whichever theory explains them.

Limits and criticism

The whole debate has a suspicious quality: it is largely a debate about how to describe a practice that goes on regardless. States concluded treaties and observed customs for centuries without agreeing on why they were bound, and they still do.

The debate earns its place for one reason. When a genuinely novel question arises, whether a new State is bound by old custom, whether a treaty permitting a monstrous thing is valid, whether a rule can bind an objector, no source settles it and the answer has to come from an account of why States are bound at all. That is when these theories stop being ornamental.

Quick revision

The question is: why is a State bound?

Naturalism: because of a higher law found by reason. Vitoria, Suarez, Pufendorf, and Grotius in part. Explains jus cogens; cannot say what the rules are.

Positivism: because States have consented, expressly by treaty or tacitly by custom. Bynkershoek, Triepel, Anzilotti. Auto-limitation (Jellinek): the State limits its own will. Explains treaty practice; cannot explain new States, jus cogens, or its own circularity.

Kelsen: validity flows from a presupposed Grundnorm, which is international, identified with pacta sunt servanda.

Sociological (Duguit, Scelle): law arises from social interdependence; Scelle's role splitting has State officials acting as organs of the international community.

Fundamental rights doctrine: States have inherent rights of independence, equality, self-preservation and jurisdiction. Now largely displaced by article 2(4) and article 51 of the Charter.

The working modern position: consent explains most of it, a peremptory core binds regardless of consent, and community interest has grown at the expense of pure bilateralism.

Three doctrines to be able to state: pacta sunt servanda (VCLT article 26), jus cogens (article 53), rebus sic stantibus (article 62).

Test yourself

1. Explain the auto-limitation theory and give the objection to it.

Jellinek's auto-limitation theory holds that since a sovereign State cannot be subjected to any will outside its own, the binding force of international law must come from the State restricting its own will. The objection is circularity: if the obligation exists only because the State wills it, the State can un-will it, and an obligation that lasts only as long as the obligor wishes is not an obligation at all. Anzilotti's response, treating pacta sunt servanda as an axiom outside the system, concedes that at least one rule does not rest on consent.

2. Why do new States create difficulty for consent theory, and how is the difficulty answered?

A State that became independent after the main body of customary law had formed never participated in making it, yet is bound by it from the moment of independence. Consent theory answers by implied consent: by entering the international community and claiming its benefits, the new State accepts its rules. The answer is a fiction, since no actual act of consent occurs and no new State has ever been permitted to opt out. The honest position is that custom binds by community acceptance rather than individual agreement, subject only to the persistent objector rule, which is available to a State that objects as the rule forms and not to one that did not exist then.

3. State article 53 of the Vienna Convention and explain which theory it supports.

A treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general international law, meaning a norm accepted and recognised by the international community of States as a whole as one from which no derogation is permitted and which can be modified only by a subsequent norm of the same character. It supports the naturalist side of the argument, since it places some rules beyond the reach of consent, though it does so in positivist language by making the community's acceptance the test.

4. What does Scelle's role splitting explain?

That international law has almost no organs of its own, so the officials of States perform double duty: a national judge applying a treaty, or a naval officer arresting a pirate on the high seas, acts both as an organ of his own State and as an organ of the international community. It explains how a decentralised system functions at all, and it is a better description of enforcement in this subject than any analogy with a police force.

5. "The theories of the basis of international law are of no practical use." Discuss.

There is force in the criticism for ordinary cases: a treaty dispute is decided by the Vienna Convention and a boundary dispute by the law of the sea, and no tribunal needs to choose between Grotius and Anzilotti. The criticism fails for hard cases. Whether a newly independent State is bound by custom it never made, whether a treaty permitting slavery is void, and whether a persistent objector escapes a rule are all questions that no source answers on its face, and each requires a view about why States are bound at all. The theories are not tools of daily practice; they are what is left when the sources run out.

6. Distinguish pacta sunt servanda, jus cogens and rebus sic stantibus in one sentence each.

Pacta sunt servanda, in article 26 of the Vienna Convention, is the rule that every treaty in force binds the parties and must be performed in good faith. Jus cogens, in article 53, is a norm from which no derogation is permitted, so that a treaty conflicting with it is void. Rebus sic stantibus, in article 62, is the narrow doctrine that a fundamental and unforeseen change in circumstances that formed an essential basis of consent may be invoked to terminate or withdraw from a treaty.