A Sentence-Based Theory of Complementarity by Kevin Jon Heller

[ Kevin Jon Heller, Senior Lecturer, Melbourne Law School, describes his recently published article, A Sentence-Based Theory of Complementarity. This article is part of the Third Harvard International Law Journal/Opinio Juris Symposium.]

Article 17 of the Rome Statute prohibits the International Criminal Court (“ICC”) from pre-empting a national prosecution of an act that qualifies as a war crime, crime against humanity, or act of genocide unless the State is “unwilling or unable genuinely to carry out” that prosecution itself. Scholars have long debated to what extent Article 17 permits states to prosecute international crimes as ordinary crimes. Proponents of the hard mirror thesis argue that such prosecutions never satisfy the principle of complementarity, because the mere act of prosecuting an international crime as an ordinary crime indicates that the state is unwilling or unable to genuinely prosecute. Proponents of the soft mirror thesis, by contrast, accept that prosecuting an international crime as an ordinary crime does not necessarily mean that the state is unwilling or unable to prosecute, but nevertheless insist that states should prosecute international crimes as international crimes whenever possible, because such prosecutions guard against unwillingness determinations and better promote the Rome system of justice.

This Article challenges both theses, demonstrating that the best reading of the Rome Statute is that states are permitted to prosecute international crimes as ordinary crimes and that discouraging states from prosecuting international crimes as ordinary crimes is counterproductive, because national prosecutions of ordinary crimes are far more likely to succeed than national prosecutions of international crimes. This Article then defends an alternative theory of complementarity that focuses exclusively on sentence. It addresses how the Court should distinguish between acceptable and unacceptable national prosecutions of ordinary crimes. It argues that the traditional complementary heuristic, which limits states to prosecuting “serious” ordinary crimes that are based on the same conduct the ICC is investigating, is inadequate and should be replaced by a heuristic in which any national prosecution of an ordinary crime satisfies the principle of complementarity as long as it results in a sentence equal to, or longer than, the sentence the perpetrator would receive from the ICC. This Article also addresses the most serious objection to a sentence-based complementarity heuristic: namely, that prosecutions for ordinary crimes fail to capture the greater expressive value of international crimes. The Article concludes by discussing less radical alternatives to the sentence-based complementarity heuristic and expresses the hope that, because of increased national capacity to prosecute international crimes as international crimes, such a heuristic may eventually be unnecessary.