I know exactly where I was 25 years ago today, on 27 June 1984. I was waiting anxiously for the reading of the Court's judgment in the Nicaragua case. I had the great honour of appearing in that case as counsel and advocate for Nicaragua, and the day of the judgment will always be an unforgettable one for me.

It would be unthinkable, on this occasion, not to recognize and salute our two senior advocates on the Nicaragua team, who are sadly no longer with us. Both were true giants in international law, and both performed magnificently in the Nicaragua case. I refer, of course, to Sir Ian Brownlie and Professor Abram Chayes.

Both Ian and Abe considered the Nicaragua case one of the most important cases – if not the most important case – that they ever argued.

Both were once my mentors and, as a young lawyer, which I once was, I could not possibly have been more fortunate than to have had the opportunity to learn from two such great teachers, advocates, and highly principled attorneys, who were thoroughly committed – in their souls – to justice, the rule of law, and the International Court.

My topic is the impact of the Nicaragua case on the way in which the International Court of Justice deals with fact-finding and matters of evidence. As a litigating attorney, a practitioner, this is a nuts-and-bolts subject that is particularly interesting to me.

I will start with the way the Court dealt with matters of fact and evidence in the Nicaragua case itself, and then discuss how the approach taken by the Court in that emblematic case has been applied in subsequent cases.

1. Fact-finding and evidence in the Nicaragua case

I will warn you now that I hold unconventional, if not heretical, views about the way the Court deals with facts and evidence. Contrary to what some commentators have said (especially on the other side of the Atlantic), and contrary to what even some of the Court's own judges have written (especially in dissenting opinions), I espouse the view – based on my own practice before the Court – that the ICJ does a very good job of receiving and reviewing evidence, and in finding the facts in the cases brought before it.

Since I litigate cases not only before the ICJ and other international tribunals, but also before national courts in the United States, I often compare how well these various judicial bodies deal with matters of fact. It is my firm view that, on the whole, the ICJ is at least as good as, and may even be better than, other tribunals in getting the facts right – especially when the evidence is abundant and highly complex.

The Nicaragua case presented the Court with by far its biggest challenge to that point in its history. It had to sort through and make sense of an enormous quantity of factual material that was necessarily complicated because of the nature of the dispute – involving armed conflict – and respond to challenging circumstances in which the facts were thoroughly and heatedly contested by the parties, as is typical when there is armed conflict. To make things even more difficult, some of the parties’ most critical actions were conducted, or intended to be conducted, in secrecy. Further complicating matters, as the Court put it, ‘the respondent State has not appeared during the present merits phase of the proceedings, thus depriving the Court of the benefit of its complete and fully argued statement regarding the facts’.Footnote ¹

To make the necessary findings of fact in this extremely difficult situation, the Court set a series of guidelines for itself, which proved useful not only in the Nicaragua case, but also in subsequent cases involving hotly disputed and complex facts.

Most importantly, the Court determined that it was appropriate to give particular weight to statements by representatives of states, including at the highest political level, that acknowledged facts or conduct unfavourable to the state represented by the person who made them. As the Court said: ‘They may then be construed as a form of admission.’Footnote ² The Court also attributed particular weight to statements by disinterested witnesses, whom it described as ‘one who is not a party to the proceedings and stands to gain or lose nothing from its outcome’.Footnote ³

By contrast, the Court decided to give little or no weight to self-serving declarations, statements, or testimony by state officials. As the Court explained:

Another important guideline adopted by the Court was that it did not treat opinions as evidence, discounting ‘any part of the testimony given which was not a statement of fact, but a mere expression of opinion as to the probability . . . of the existence of such facts, not directly known to the witness’.Footnote ⁵ The Court also decided not to treat as evidence reports in press articles or books, and to adopt a very cautious approach to what constituted public knowledge. As it explained, wisely in my view: ‘Widespread reports of a fact may prove on closer examination to derive from a single source, and such reports, however numerous, will in such case have no greater value as evidence than the original source.’Footnote ⁶

These, in effect, were the rules of evidence that the Court applied in equal measure to both parties in the Nicaragua case, and they are, I submit, unimpeachable. Certainly, to those of us who litigate regularly, these are precisely the rules of evidence we would expect to be applied by any competent court.

In the Nicaragua case, there were three main areas of factual dispute to which the Court applied these rules. A quarter-century ago, it was principally my role on Nicaragua's team, as instructed by the Agent, Ambassador Arguello, to develop and present the evidence on these issues. Although much time has passed, the facts are as vivid to me today as they were then.

The first issue was whether, as Nicaragua had alleged, the United States had recruited, organized, supplied, trained, and directed a paramilitary force – the Contras – for the purpose of carrying out military activities inside Nicaragua against the government of that country. This was one of the central elements of Nicaragua's claim that the United States had engaged in the illegal use of force, and had unlawfully intervened in its internal affairs and violated its sovereignty and territorial integrity.

This was the easiest factual issue for the Court to resolve. US encouragement, support, and direction of military activities in and against Nicaragua were undisputed by the United States, both in the earlier rounds of the case in which it appeared and publicly. Indeed, the US administration at the time vociferously proclaimed its military support of the Contras, and financed them expressly in US legislation enacted openly and in public session. Applying the guidelines it developed to weigh the evidence, the Court found that the United States, at the highest level of government, had admitted the veracity of Nicaragua's allegations numerous times in its national legislation, its statements before the US Congress and international organizations, and its public pronouncements.

The second issue was whether all of the specific activities of the Contras could be imputed to the United States, so that the United States would be legally responsible for them. Here, the Court determined as a legal matter that US responsibility would require a showing of complete dependence of the Contras on the United States, such that they were a de facto organ of the US government, or that the United States actually exercised direct control over their day-to-day operations. On the issue of attribution, I hold the view that the Court might have applied a legal standard that was too restrictive, to the benefit of the United States. But I would have difficulty arguing with the Court's factual findings that the Contras were heavily, but not completely, dependent on the United States and that, while the United States manifested overall control over them, it was not fully established that the United States was regularly exercising direct operational control over all of their military activities. This might have been the case, but the evidence establishing it was imperfect, and the Court was not incorrect to reach that conclusion.

The third factual finding by the Court is the one that has been used by critics of the Court, especially in Washington, not only to attack the Judgment, but, most unfortunately, to attack the Court as an institution. According to these critics, this factual finding demonstrates that the Court is hopelessly incompetent as a finder of fact. Notably, it was only after – and in response to – the Nicaragua decision that the United States adopted such a view. Sadly, it has been repeated often enough over the past 25 years that many American, and even some European, commentators have come to accept it as gospel. But, to paraphrase the Court, these ‘reports’, however often repeated, have no greater value than their original source, so it is worth examining.

The finding by the Court to which I am referring is that the evidence before it failed to support the US allegation that the government of Nicaragua had engaged in an armed attack against El Salvador, by sending weapons to guerrillas in that country. The United States used this allegation to justify its own use of force against Nicaragua as a purported exercise of the collective self-defence of El Salvador. The Court rejected this argument on legal grounds, finding as a matter of law that, even if had been proven that Nicaragua were supplying arms to El Salvador, this would not in itself constitute an armed attack sufficient to justify the use of force against Nicaragua. The Court also found lacking several other elements, necessary under customary international law, to justify military action against Nicaragua as self-defence or collective self-defence.

On the issue of whether there was an armed attack sufficient to justify self-defence, the Court not only got the law right; it was also right on the facts. In my view, the Court's conclusion that the evidence did not support the US allegations against Nicaragua was plainly correct. The evidence came nowhere close to supporting those allegations. To prove a negative – never an easy thing to do – Nicaragua produced a witness at the oral hearings who had served as an intelligence analyst for the CIA, and whose principal duty was to analyse all of the intelligence relating to alleged Nicaraguan arms trafficking. As you might imagine, this was very dramatic testimony. Most of the judges were perched on the edges of their seats, listening intently. The CIA witness testified that, although the most sophisticated intelligence techniques and equipment were employed, and it was an extremely high priority for the US government to catch Nicaragua in the act, no evidence was obtained, at any time prior to or during the case, of any Nicaraguan arms shipments to El Salvador. None whatsoever. The witness testified that, if there had been any such arms trafficking, it would not have escaped detection by the United States. This testimony was supported, in the Court's view, by the failure of both the United States and anyone else to physically intercept, or produce evidence of, any actual shipment of arms by the government of Nicaragua.

As the Court observed:

To me, especially as a trial lawyer, it is very difficult to find fault with the Court's logic or its factual findings on this issue.

The manner in which the United States presented its evidence purporting to show Nicaraguan arms-trafficking did not make the Court's fact-finding task easier. As indicated, the United States did not appear for the merits phase. However, while the oral hearings were in progress, the US Embassy in The Hague forwarded to the Court a lengthy document prepared by the State Department. The document, which bore the overtly partisan title, Sandinista Intervention in Central America, contended that Nicaragua was guilty of supplying a substantial and steady flow of arms to guerrillas in El Salvador.

Nicaragua had a good argument that the submission of the document in this manner, in the middle of oral hearings, was both highly prejudicial and a blatant violation of the Court's rules, and should have been disregarded. There is little doubt that, in a normal case in which both parties have appeared, the Court would not have allowed one of them to spring such a document on the other at the oral hearings. However, mindful of its obligation under Article 53 of the Statute to satisfy itself, in the absence of the respondent state, that the claims of the applicant state are well founded in fact and law, the Court decided to take the State Department document into account. If anything, this showed how determined the Court was to objectively and impartially determine the facts of the case.

Applying the guidelines it established for review of all the evidence, including that submitted by Nicaragua, the Court found the US document unpersuasive. It turned out to be nothing more than a collection of self-serving statements by US government officials, newspaper reports, and other unsupported allegations accusing Nicaragua of supplying arms to the Salvadorean guerrillas. There was no first-hand, objective, or impartial evidence to support these allegations. The Court rejected them on the same basis as it rejected the self-serving statements of Nicaragua's government officials.

Only one judge disagreed. Judge Schwebel's dissent vehemently attacked the Court's fact-finding because it did not embrace the State Department's submission, which was really, upon close examination, no more than a rehash of the US government's recurrent political attacks on Nicaragua, made for the purpose of winning the approval of the US Congress for military assistance to the Contras. In my view, no serious court, anywhere, would have given significant evidentiary weight to these polemics. That explains why not a single other judge joined in this dissent, or expressed disagreement with the Court's fact-finding on this issue, or found any other support in the record for the US attempt to justify its conduct on grounds of collective self-defence.

Unfortunately, over the ensuing 25 years, critics of the Court have used the dissenting opinion in the Nicaragua case to challenge the Court's competency in matters of evidence and fact-finding. This criticism does not withstand an analysis of the actual evidence in that case, or the manner in which the Court treated it. The critics simply do not know the evidence. Nevertheless, they have had effect in some quarters, in unfairly undermining the reputation of the Court as a competent finder of the facts, and its reliability as a judicial institution.

2. Fact-finding and evidence after Nicaragua

In my view, the Court's competence in dealing with evidence and finding the facts has been demonstrated repeatedly, especially in difficult fact cases over the quarter-century following the Nicaragua decision. Two prominent examples, which again offered the Court an opportunity to address vigorously disputed and complex factual situations attendant to armed conflict – arguably the most difficult fact situations a court may be called upon to address – are DRC v. Uganda and the Bosnia Genocide case.Footnote ⁸ For the record, I applaud neither judgment, and I share some of the criticism that has been made of the Court's legal reasoning and conclusions, especially in regard to the extremely high bar the Court established, citing the Nicaragua case, for the attribution of responsibility to the respondent state for the actions of armed groups fighting alongside its military forces or under their overall direction. But, wise or not, this is a legal standard set by the Court. It does not detract from the Court's diligent and competent review and interpretation of the masses of factual material, much of it vigorously contested, placed before it in those cases.

In both cases, the methodology applied in the Nicaragua case is visible: particular weight is given to statements against interest by representatives of states, and to statements by disinterested witnesses; self-serving declarations by government officials, especially in the context of litigation over armed conflict, are treated with great reserve. Press reports are not treated as evidence to prove particular facts, although they may serve as useful context to corroborate facts supported by independent evidence.

In these subsequent cases, the Court introduced a new guideline, also helpful: it chose to give particular weight to the factual findings of other highly credible judicial or quasi-judicial bodies (the ICTY in the Genocide case and the Porter Commission in the DRC case), and to the unbiased reports of international organizations expert in the subject matter. These guidelines have been especially helpful to the Court in its review and evaluation of the evidence in a number of cases.

As recently as last year, in Argentina v. Uruguay, the Court again showed its capacity to review, analyse, and interpret a massive amount of factual material, this time of a highly technical and scientific nature.Footnote ⁹ Faced with conflicting reports and testimony of experts retained by the parties, the Court wisely decided to treat all of this evidence with caution, and instead to place special weight on the reports prepared by independent experts retained by the World Bank – an international organization it regarded as unbiased and expert in the subject matter.

Here again, the Court got the facts right. This was demonstrated unequivocally shortly after the judgment, when, at the Court's direction, the parties agreed to and carried out joint monitoring of the pulp mill that had been accused of polluting the Uruguay River, and jointly found that there was no evidence of pollution – just as the Court had determined.

To be sure, the ICJ faces a number of challenges when it performs the role of fact-finder. It tends to depend completely on the parties themselves to produce the evidence. It makes infrequent, some would say too infrequent, use of its powers under the Statute and Rules to take the initiative and request evidence from the parties, or from other sources. I think there is some basis for criticizing the Court's deliberately passive role in evidence production and in its reluctance to draw adverse inferences from a party's failure to produce critical evidence in its possession, as underscored in Vice-President Al-Khasawneh's dissent in the Genocide case.Footnote ¹⁰ Another handicap is the unwieldiness of presenting live testimony, and cross-examination, before a panel of 15 (and sometimes even 17) judges from diverse legal cultures.

However, what compensates for these factors is a significant material advantage the ICJ has over many other courts or tribunals, including national courts. The ICJ has a Registrar and a well-trained, experienced, and highly competent staff of lawyers to assist the judges and help the Court to assemble, process, and understand the evidence in difficult and complex factual situations, especially those involving mountains of documents and conflicting technical reports. In my view, the ICJ's record of success as a finder of fact both in and since the Nicaragua case is attributable first and foremost to the diligence and dedication of the judges themselves. But it is also due, in my opinion, to the capability, professionalism, and hard work of the Registrar and his staff of lawyers.