Sources Essay Notes

Starting point: Art 38 of the Statute of the International Court of Justice (ICJ), 1945

Note: Art 38 is technically limited to sources of international law which the International Court must apply. However, there is no serious contention that it expresses the universal perception of the sources of international law, because

• The function of the International Court is to decide disputes submitted to it “in accordance with international law”

• All member states of the United Nations are ipso facto parties to Art 38 by virtue of Art 93 of the united Nations Charter (further, states that are non-members of the UN can specifically become parties to Art 38)

• Many subsequent treaties and conventions, like UNCLOS 1982, refer to it.

1 Treaties

Article 38 refers to treaties as “international conventions, whether general or particular, establishing rules expressly recognized by the contracting states”

The obligation to follow a treaty once has ratified is derived from CIL – the principle of pacta sunt servanda. See also Art 26, VCLT.

If the content of the treaty reflects CIL, then the rules of the treaty, not the treaty itself, becomes binding upon all States, regardless of whether they are parties to the treaty. The CIL will also continue its separate existence (see below on the relationship between customs and treaties).

In the past, there was debate about whether or not treaty obligations amounted to international law. The German philosophical tradition was to treat treaties like contracts. It is not a legal system, merely an agreement.

• Fitzmaurice argued that the only law that is relevant here – that the obligation must be carried out – which is derived from an antecedent general principle of law: pacta sunt servanda.

• There might be treaties which codify existing law. But in those scenarios, the state parties to the treaty will not be following the treaty as much as it is following the law. The treaty is merely an instrument in which the law is conveniently stated and evidence of what it is, but is not in itself law.

• Even if a treaty obligation eventually becomes law, the treaty itself will not be the source of this new law: it will be custom, as more and more states practice the rule.

2 Custom

Article 38(1)(b), Statute of the ICJ: “international custom, as evidence of a general practice accepted as law”

Formation

For a new customary rule to be formed, there must be (i) relevant acts of the states concerned amount to a settled practice and (ii) opinio juris. These two elements are respectively an objective (behaviour) and subjective (belief) criterion.

• Nicaragua v USA

Facts and verdict: Nicaragua claimed the US had used armed force and intervened in its affairs contrary to international law. The Court could not consider US ability under the UN Charter and other multilateral treaties because of a US reservation to its acceptance of the Court’s jurisdiction that excluded “disputes arising under a multilateral treaty”. Yet, the court ruled that customary rules on armed force and intervention continued to bind the US in parallel with the obligations under the UN charter and other multilateral treaties

At 207: “...for a new customary rule to be formed, not only must the acts concerned "amount to a settled practice", but they must be accompanied by the opinio juris sive necessitatis.”

State practice

1. What counts as state practice?

Omissions are relevant where actions, in particular protests to the actions of other States, are expected. Such circumstances usually arise where a State violates international law. If other States omit to protests, this can be taken as evidence of acquiescence, which is itself evidence that the acquiescing State regards the activity or state of affairs as consistent with international law. The acquiescing State may be counted as a supporter of the rule in question along with any States whose positive actions have contributed to the ‘general practice accepted as law’.

• Anglo-Norwegian Fisheries Case (1951) ICJ Rep 116, at 138, which states that acquiescence cannot be established unless a state has actual or constructive knowledge of the claim being made.

• Navigational and Related Rights (Costa Rica v Nicaragua) (2009) ICJ Rep 213

Facts: Nationals of Costa Rica used to fish on Nicaraguan territory, without the latter’s consent. This kind of behaviour calls for protest from Nicaragua, but the latter remained silent on the issue.

Verdict: Nicaragua’s silence in these circumstances amounted to acquiescence.

At para 141: “For the Court, the failure of Nicaragua to deny the existence of a right arising from the practice which had continued undisturbed and unquestioned over a very long period, is particularly significant.”

Protests are relevant too. In situations where States violate international law, if the other States protests, this strengthens the existing international rule – in this sense, breaches of CIL followed by condemnation by other States strengthens the CIL.

International Law Commission considers that the “records of the cumulative practice of international...

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