Methodological Approaches to Customary International Law by International Criminal Tribunals

Abstract

In the previous chapter I argued that the role of the judge is to apply the law, with restricted possibilities to develop the law in relation to new factual circumstance. Judges are, however, not allowed to create law when merely “determining” customary international criminal law. When the applicable law consists of unwritten norms, the question is whether judges should have an obligation to disclose the method used to determine a customary international criminal norm. When the ICRC published its customary international humanitarian law study it chose to disclose the method used to identify customary law, listing what it considers to be relevant State practice and opinio iuris. The ICRC itself simultaneously claimed that the separation of State practice and opinio iuris is “very difficult and largely theoretical.” Although the ICRC Custom Study has been subject to critique, the disclosure of method is to be welcomed in that it allows the ascertainment of customary international law to be comprehensible. However, one could argue that the role of international criminal tribunals is to deliver judgments and that—to draw on Pellet’s comments on the ICJ—they are only judicial bodies and not teachers or scholars in relation to the underlying methodology. Nevertheless, it is maintained here that the issue is different with regard to criminal proceedings. An accused is entitled to know the exact underlying jurisdictional legal basis of the charges against him, whether they form part of conventional or customary international criminal law, and similarly a convicted criminal is entitled to comprehend the legal basis of his conviction. A part of the fair trial guarantee is that the rationale of a trial judgment shall be explained, accompanied by a reasoned opinion. This obligation on the part of the trial chambers safeguards the accused’s right of appeal, and that the Appeals Chamber can evaluate the Trial Chambers findings. In practice Appeal Chambers have rebuked Trial Chambers for their evaluation of factual evidence. While overturning certain customary law findings of the Trial Chambers, such as the result, the Appeal Chambers have rarely criticized the applied methodology of the Trial Chambers. Since the rationale or legal reasoning of a judgment must clearly be explained, the underlying legal basis of the criminal conviction must have already been clearly set out as a prerequisite. In relation to “ordinary” domestic statutory criminal norms this problem does not generally arise. As established above in the domestic context, the nullum crimen sine lege certa requirement as an “imperative for improvement” is addressed to the legislator to define ex ante the underlying criminal norms with adequate precision. Ideally, everyone who can read should be able to comprehend the underlying legal basis as long as the criminal norms are drafted in a clear and comprehensible manner. For customary international criminal law the matter is far more complex. Here the disclosure of how the respective chamber arrived at a customary international criminal norm is a necessary element therewith an individual can comprehend the legal reason and normative basis of his conviction, and as such be able to challenge possible methodological shortcomings on part of the judges. However, judges are often reluctant to disclose the applied method(s). Like magicians, the judges are not willing to reveal how they pull the rabbit—customary international criminal law—out of the hat. The opportunity to quantify the way customary law is determined by international criminal tribunals begins with a duty to disclose the method used. On the basis of the disclosed method one would be in a position to verify or challenge a judgment or decision, that is to say, if it had been delivered on sound methodological grounds. Regrettably, this proposed duty of a methodological disclosure is far from being a political and legal reality.