LWN158: Public International Law

Seminar 2: Sources of Public International Law

This week’s objectives:• To appreciate the categories of sources of public international law

• To identify the elements of customary international law and critically evaluate the means of establishing a rule of customary international law.

• To consider particular exceptions to the scope of customary international law including the ‘persistent objector’ principle as well as the establishment of non-derogable rules (jus cogens).

• To understand the creation and application of rules of local custom.

• To understand the operation of other sources of international law, including general principles, the writings of jurists and the emerging role of UN Resolutions – both of the GA and the Security Council.

What are the sources of public international law?

• Last week we talked about international law being formed by consensus of States.

“International law governs relations between independent States. The rules of law binding upon States therefore emanate from their own free will as expressed in conventions or by usages generally accepted as expressing principles of law and established in order to regulate the relations between those co-existing independent communities or with a view to the achievement of common aims. Restrictions upon the independence of states cannot therefore be presumed.”

Lotus case (France v Turkey) (1927, PCIJ Reports, Ser A, No 10):

• How does that process create law?• What forms does international law take?• Starting point: Statute of the International Court of Justice, art 38(1)

• Sets out the law which the ICJ can use to resolve disputes between States• Taken to be authoritative list of the sources of international law

ICJ Statute, Article 381. The Court, whose function is to decide in accordance with

international law such disputes as are submitted to it, shall apply:

a) international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;

b) international custom, as evidence of a general practice accepted as law;

c) the general principles of law recognized by civilized nations; d) subject to the provisions of Article 59, judicial decisions and the

teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

Sources of law:• From article 38(1):

(a) Treaties (next week)

(b) Custom

(c) General principles of law

(d) Cases and writings of eminent scholars

Customary international law

• Practices of states crystallised into normative rules: rules for how states should behave derived from how they have behaved in the past

• Customary international law vs treaties– Custom bind states even where no treaty exists

– Custom can influence the development of treaty, and vice versa

• Rationale: – Consensual foundation of international law (Lotus)

– Reliability and enforceability of regular practices

– Good faith

Elements of customary international law

Art 38(1)(b): ‘international custom, as evidence of a general practice accepted as law’

State practice:

• Evidence of ‘general practice’ of states

• Objective element

Opinio juris• ‘Accepted as law’: States recognise themselves as obliged to so act

•Subjective element

North Sea Continental Shelf cases: two elements:

State practiceTriggs:

• ‘If there is no persistent opposition to the practice, and where there is acquiescence or positive acceptance that it is useful, over time the practice may become regarded as obligatory.’

• Common usage of a particular practice will become custom where there is ‘sufficient recurrence or repetition of an act that can be proved by reference, for example, to diplomatic actions between states, the practice of international organisations, and the decisions of national and international tribunals.’

• Custom is ‘inferred from repeated and consistent state actions.’

State practice cont/...• Consistency, duration and generality

– Fisheries Jurisdiction case (UK v Iceland) (Merits): ‘common, consistent and concordant’

– North Sea Continental Shelf: ‘widespread and representative participation’ by ‘states whose interests are especially affected.’

– Nicaragua (Merits): ‘consistent, but not absolutely rigorous conformity’.

• Evidence: official speeches, parliamentary proceedings, domestic legislation, decisions of domestic courts, historical records, press releases and communiqués, policy statements, comments by governments, voting records, treaties

• (Note: these things can also be evidence of the next element – opinio juris)

Opinio Juris

• States must believe that they are legally obliged to follow the relevant practice in order for it to become custom

‘The frequency, or even habitual character of the acts is not in itself enough. There are many international acts…which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty.’

Lotus case (France v Turkey), a p 28

Opinio juris

• Do you think this is a useful definition?

• More modern cases look for objective evidence of this subjective element: – Examination of state practice, looking for evidence of attitude of

state which motivates their activities

– The feeling on the part of the states that in acting as they act they are fulfilling a legal obligation

West Rand Central Gold Mining Company (1905)

Before a rule becomes custom there must be evidence that it is ‘of such a nature, and has been so widely and generally accepted, that it can hardly be supposed that any civilised State would repudiate it.’

Opinio Juris cont/...• North Sea Continental Shelf case:

– Denmark and the Netherlands tried to argue that a treaty rule applied to Germany because it had become customary law (even though Germany was not a party to the treaty)

– ICJ held that there was ‘not a shred of evidence’ that non-states parties acted in accordance with the rule because they ‘believed themselves to be applying a mandatory rule of customary international law’.

• Nicaragua (Merits): evidence that prohibition on use of force in UN Charter had become customary law, and that both Nicaragua and US had demonstrated opinio juris supporting this conclusion

State practice, opinio juris and deviations from the rule• The fact that some states may in practice deviate from

the rule does not deprive the rule of legal status if opinio juris persists.

• Eg: in Nicaragua (Merits) there was evidence that states violated rule against the use of force but those States justified such action based on exceptions to rule, not by arguing that rule didn’t exist.

• Eg: there is evidence that some states continue to torture prisoners, but no state argues that torture is permissible. The fact of some contrary state practice does not negate opinio juris in favour of the prohibition against torture.

“Instant custom”?

• North Sea Continental Shelf: rules of custom can emerge in a short period of time, but in such a case state practice should be both extensive and virtually uniform.

• Norms can form rapidly in response to new problems, eg outer-space law, exclusive economic zone

• Scharf, ‘Grotian moment’: paradigm-shifting development in which new rules and doctrines of customary international law emerge with unusual rapidity and acceptance – eg emergence of new rules of international criminal law following atrocities of WWII.

• Chen, ‘instant custom’ through General Assembly resolutions.

• Do you think GA resolutions are sufficient to create new binding norms?

Persistent Objector• General rule: customary international law binds all states, even without

their explicit consent, even when there’s no specific evidence that they have adhered to the practice.

• But where a State has persistently objected to the rule they may escape being bound by it.

• Anglo-Norwegian Fisheries: – If a state opposes the rule early on and maintains its opposition consistently, it will

not be bound by the rule.

– Significant that other states had tolerated Norway’s system

• Triggs: no longer much support for persistent objector rule. More common for states to argue that rule doesn’t exist, or that some exception applies in given situation, rather than to argue that rule exists but doesn’t apply to them.

• Can you see any problem with allowing the persistent objector rule?

Jus cogens• A rule of jus cogens, sometimes known as a ‘peremptory

norm,’ is a special category of customary international law

• Vienna Convention on the Law of Treaties, art 53: norm accepted and recognised by the international community of States as a whole as a norm from which no derogation is permitted.

• Eg prohibitions on genocide, slavery, torture, piracy

• Cannot be overridden by treaty

• Persistent objector rule does not apply

Regional custom• It is possible for customary international law to apply to a small group of

States, such as those of a particular regional area

• Asylum case: regional custom could exist establishing a rule which would bind a group of states– Would require:

– ‘Constant and uniform usage practised by the states in question’ (state practice) – so arguably a higher standard than for general custom

– ‘Usage is the expression of a right appertaining to the state granting asylum and a duty incumbent on the territorial state’ (opinio juris)

– Insufficient evidence of these elements

– And in any event, Peru had persistently objected to the rule and it would not therefore be opposable against that state.

• Right of Passage case: ICJ did find sufficient evidence of local custom: ‘long continued practice between states formed the basis of mutual rights and obligations’

General Principles of Law Article 38(1)(c)

Technically no hierarchy among 38(1)(a), (b) and (c), but general principles tend to be applied to fill gaps where there is no applicable treaty or customary rule.

Schacter: five categories1. Principles of municipal law ‘recognised by civilised nations’2. General principles of law ‘derived from the specific nature of the

international community’3. Principles ‘intrinsic to the idea of law and basic to all legal systems’4. Principles ‘valid through all kinds of societies in relationships of hierarchy

and coordination’5. Principles of justice founded on ‘the very nature of man as a rational and

social being’

• Examples include rules of equity, rule against unjust enrichment, principle that obligations should be complied with in good faith, procedural rules.

Judicial decisions and teachings• Article 38(1)(d): Judicial decisions and the teachings of the

most highly qualified publicists of the various nations

• Subsidiary sources of law – other three sources take priority

• Eg decisions of ICC, ICJ, ICTR and ICTY, especially statements of law and interpretations found in judgments

• Writings of eminent authors, especially those who have been judges of the ICJ or other well-regarded experts.

• Particularly useful for cases looking at novel areas, where an issue has not been addressed by law or judgments

Discussion Questions:1. What sources of law may the ICJ consider in determining

the obligations of states? Do some sources take priority over others?

2. Why is opinio juris a requirement for the establishment of customary international law?

3. If customary international law can develop without uniform state practice, does this impinge on the sovereignty of other States?

4. Does the doctrine of the persistent objector undermine the force of customary international law?