International law is ready for a period of renewal in this post-post-modern era. I predict this renewal will come from reviving classical doctrines, such as the positive-law doctrine of sources, and from revisiting formalism, (1) Such renewal will not be possible for the international law of evidence because there is no classical doctrine. Perhaps, as Charles Brower suggests, this is because of the differing civil and common law attitudes toward the rules of evidence, especially with respect to the burden of proof. (2) It seems to me, however, that we need a law of evidence in international law, especially for the international law on the use of force. Rules regulating force need to be as clear as possible and so do the roles that support the substantive principles, such as the law of state responsibility and the law on evidence--the clearer the rules, the less discretion available to states, and the greater the chance of actually restraining the use of force in international law.
Plainly international law does not currently have a well-developed body of evidentiary rules on the use of force. According to Lobel:
Questions involving the standards and mechanisms for assessing
complicated factual inquiries are generally not accorded the
same treatment given by the legal academy to the more abstract
issues involved in defining relevant international law standards.
Unfortunately, international incidents generally involve
disputed issues of fact, and in the absence of an international
judicial or other centralized fact-finding mechanism, the ad hoc
manner in which nations evaluate factual claims is often
The International Court of Justice has made statements regarding what is credible evidence, evidence to be given "weight" in international cases. It has not, to date, made any straightforward, express statement of the standard of proof expected. We generally know which party carries the burden, but we do not know with certainty what the burden is. Still, there are indications in international law that the standard should be something like the clear and convincing standard found in the United States. In the United States, the burdens are generally characterized as (1) preponderance of evidence; (2) clear and convincing evidence; or (3) evidence beyond a reasonable doubt. Several judicial decisions, scholarly comments, and examples of State practice support the clear and convincing standard for evidence.
For example, several self-defense cases, including the Oil Platforms case (2003) and the Nicaragua case (1986), indicate that the ICJ wanted more than a mere preponderance of the evidence to support claims of the United States that it acted in self-defense. On the other hand, there is no indication that the United States had to provide proof beyond a...