A Clear Standard of Proof in Disputes Before the ICJ: Are We There Yet?

On January 23 exactly a year ago, the International Court of Justice (ICJ) passed an order for provisional measures in the case concerning the Application of the Convention on the Prevention and Punishment of the Crime of Genocide between The Gambia and Myanmar. The order and its implications have been analysed and explained by several commentators: see here, here, and here. But one aspect of the case which has stood out is the noticeable difficulty of meeting the strict standard of proving Myanmar’s responsibility for having committed genocidal acts. While the hearing on merits is yet to commence, the order has revived two questions about this procedural issue: what is the standard of proof that the ICJ employs and whether it is possible to infer a reasonably clear standard of proof from the ICJ’s decisions. This piece is an attempt to answer these questions.

Demystifying Standard of Proof and its importance

Standard of proof is usually understood in conjunction with the concept of burden of proof, both of which are products of fact-focussed adjudication in both domestic and international legal systems. While the latter plays an allocative role by placing the responsibility to prove a fact on someone, the former defines the extent of proof that has to be provided. The burden of proving the existence of a fact is on the party that asserts the fact. This rule has also assumed the status of a “well-established” rule of procedure in international adjudication.

However, the distinctions between civil law and common law systems make it difficult to establish a common degree of proof. While common law distinguishes between standards of proof based on the nature of the dispute as civil or criminal, civil law systems disregard any such differences and instead rely on the personal conviction of the judge. The lack of adherence to a single system in international law has resulted in varying standards of proof in cases before the ICJ.

Over the years, adjudication before the ICJ has become fact-heavy with the Court increasingly focussed on ascertaining the existence of disputed facts. There has been a marked transition from a hands-off approach in fact-finding to an active one in fact-heavy disputes. Legal provisions also signify the importance of the ICJ’s fact-finding role: Article 49 of the Rules of the Court requires States to submit a Memorial containing a statement of facts and the Counter-Memorial to contain an admission or denial of the facts. Article 36(2)(c) of the Statute of the Court makes a reference to ‘facts’, which constitute a breach of an international obligation, as a basis for the Court’s jurisdiction. Since claims by States and the eventual basis of the Court’s judgment rest on facts, it is necessary to have a standard of proof to guide both the Court, in determining the existence of fact, and parties, in adducing evidence in proof of those facts.

Examining the ICJ’s position on the standard of proof

The earliest case, which is also the first case that the ICJ decided, in which it enunciated the standard of proof was the Corfu Channel case. The dispute, initiated by the United Kingdom, related to Albania’s alleged role in laying down mines or having allowed a third State to do so, the explosion of which had caused damage to British warships passing through the Corfu Channel. In its judgment holding Albania responsible, the Court used as many as three expressions to describe the standard of proof: decisive legal proof, conclusive evidence, and a degree of certainty. While it might seem that the three different standards (‘decisive’, ‘conclusive’ and ‘certainty’) were nothing more than adjectives used interchangeably, the creative use of multiple words was at cost of predictability in the Court’s approach.

In Oil Platforms, Iran alleged that United States’ (U.S.) warships had destroyed oil production complexes in violation of the Treaty of Amity 1955 and international law. The U.S. premised its defence on the right self-defence on account of the alleged Iranian attack on its own vessel Sea Isle City. In refuting this contention, the Court employed two standards of proof: sufficiency of the evidence and conclusive evidence in holding that the U.S. had failed to discharge the burden of proof. The use of both terms was ambiguous since evidence need not always meet both the standards: it may be sufficient without being conclusive. But the Court failed to clarify whether the evidence had to meet both the standards in order to be considered.

Judge Buergenthal called out the Court for changing the standard of proof from sufficient to conclusive “without an explanation” and for the confusing use of various terms to describe the standard. Other judges joined in pointing out the problems with the Court’s approach. Judge Owada wanted the Court to “engage in much more in-depth examination” of the issue of fact-finding and standard of proof. Judge Higgins was more trenchant in her critique. She felt that it was expected of the Court to have “clearly stated the standard of evidence” especially in a case that crucially depended on evidence. Judge Higgins also criticised the Court’s use of standards like sufficient and conclusive without adequately defining them.

In the Bosnian Genocide, the Court dealt with the issue in a more precise manner.  The case brought by Bosnia and Herzegovina related to alleged violations of the 1948 Genocide Convention by the Federal Republic of Yugoslavia. Both the parties argued for two entirely disparate standards of proof. While the Applicant, who was faced with the unenviable task of proving genocidal intent, demanded a ‘balance of probabilities’ standard, the Respondent wanted stricter standards of ‘beyond reasonable doubt’ and proof of a ‘proper degree of certainty.’

The Court reiterated the standard laid down in Corfu Channel: “claims against a State involving charges of exceptional gravity must be proved by evidence that is fully conclusive.” It, however, interchanged ‘certainty’ with ‘conclusive evidence’ in the earlier dictum lending credence to the fact that the standards in Corfu Channel were just an exercise in the creative use of vocabulary. It also introduced a new standard of “fully convincing” evidence which was ostensibly inspired from the standard laid down in Armed Activities on the Territory of the Congo. This standard applied both to allegations of commission of genocidal acts and to proof of attribution of the acts to the State. For allegations of failure to prevent the commission of genocidal acts and to punish the persons charged, the Court demanded “proof at a high level of certainty appropriate to the seriousness of the allegation.”

Moving towards predictable standards of proof

While a search for explicitly defined standards of proof in the ICJ’s judgments yields a disappointing answer, it might be possible to infer them after the Bosnian Genocide decision. The decision is now used to argue that the standard of proof has to be ascertained in relation to the gravity of the charges or claims before the Court. Halink has visualised the Court’s approach as a sliding scale with cases involving serious allegations such as genocide on one end of the spectrum and cases of low gravity on the other. Wilkinson has analysed the differing degrees on the basis of classification of the Court’s functions as declarative and determinative. In cases that attract the Court’s declarative function, such as defining a boundary between States, it employs a lower standard of proof which resembles the ‘preponderance of probabilities’ criterion. On the other hand, where the Court is asked to determine the legality of actions, such as in the Bosnian Genocide, it uses a higher standard of proof. Even Judge Greenwood in his separate opinion in Pulp Mills found that a lower standard of proof in cases involving less grave allegations is implicit in the Court’s dictum in the Bosnian Genocide case. He considered cases concerning violations of environmental obligations as part of the category of cases that require only proof on a ‘balance of probabilities’ basis. This was because the application of a high standard of proof in environmental disputes “would have the effect of making it all but impossible for a State to discharge the burden of proof.” He seems to have devised another criterion to determine the appropriate standard—the degree of onerousness in providing proof.


It may now be argued that in a certain type of cases such as those involving breaches of environmental obligations or human rights obligations, the standard of proof should be low. Despite the appeal of these analyses, they remain only inferential and the ‘high-low’ thresholds are ill-defined offering little guidance to prospective litigants before the ICJ. This is why the upcoming adjudication between The Gambia and Myanmar gains significance given the perfect opportunity that the ICJ has to explicate its position on standards of proof. This is not only important but necessary both for states and the Court itself.


Advaya Hari Singh is a final-year law student at Maharashtra National Law University, Nagpur, India, with an interest in public international law. He is currently a research assistant to Dr. Aniruddha Rajput, a Member of the International Law Commission.