The principle of complementarity, which governs the International Criminal Court (ICC), will inevitably require some difficult determinations about whether a national proceeding warrants deference. One may discern in the literature three major theories about what the ICC should scrutinize when it assesses a national proceeding: the nature of the charges laid, the severity of the sentence imposed, or the quality of the process adopted. These three approaches are not necessarily mutually exclusive; they can be combined in different ways and with different emphases to create plausible schemas.
Kevin Jon Heller’s article, A Sentence-Based Theory of Complementarity, makes a valuable contribution to the discussion. He advances an important and convincing critique of approaches that would focus on the domestic or international nature of the charges or on the relative gravity of the charges. He proposes to replace such approaches with one focused on the sentence. While Professor Heller may be successful in showing that a sentence-based approach is superior to a charge-based approach, I will argue that a sentence-based approach also raises some serious difficulties that have not been addressed. I will therefore suggest a third option, a process-based approach. I believe that a process-based approach is not only the best fit with the Rome Statute (the positive law); it is also the most elegant theory. Under a process-based approach, the Court can refer to charges and sentences as indicia, insofar as they shed light on the genuineness of the process.
While I have reservations about the more radical proposal to adopt a new approach to complementarity that focuses exclusively or even primarily on sentence severity, I believe that A Sentence-Based Theory of Complementarity offers two important insights. The first demonstrates the very limited role that should be accorded to “charges.” The second demonstrates the potentially important role that can, in some circumstances, be accorded to “sentences.” I would absorb these insights into a process-based theory.
Heller also raises concerns about the “same conduct” test adopted by the ICC. Similar concerns have been raised in other recent thoughtful scholarship, so it is valuable to inspect the concerns here. While I agree that some flexibility is needed, I hope to show that the problem is actually much narrower than is often perceived in the literature. The Rome Statute already provides solutions to the scenario where a state wishes to prosecute a person for a different crime. These solutions include a consultation mechanism to prioritize cases as well as the “interests of justice” test. In my view, stretching the admissibility regime to cover such scenarios is not only unnecessary but would generate incoherencies. Thus, while I partly agree with the concerns raised by Heller and others, I will argue for a much narrower solution.
All references to “admissibility” in this comment concern the complementarity aspects of the Rome Statute—Article 17(1)(a)–(c))—and not the distinct issue of “gravity” (Article 17(1)(d)).
 Kevin Jon Heller, A Sentence-Based Theory of Complementarity, 53 Harv. Int’l L.J. 85 (2012).
 Id. at 88–107.
 Id. at 107–30.
 Rome Statute of the International Criminal Court, Jul. 17, 1998, UN Doc. A/CONF.183/9, 2187 U.N.T.S. 90 [hereinafter Rome Statute].
 See generally Heller, supra note 1.
 Id. at 107–30.
 See infra note 53.