Chapter 2 discusses “systemic effect,” which refers to the impact of the Rome Statute and the ICC on domestic legal systems. The systemic effect of the Rome Statute is presumed to be mainly through the application of the “complementarity” framework. The chapter argues that complementarity is not the main avenue to systemic effect, mainly because it is a court-centric notion that has often resulted in an adversarial relationship between the Court and national authorities. This has meant that at times the Court and national authorities compete for cases, as the national authorities seek to avoid the Court’s intervention. Instead of true complementarity, it may be more accurate to speak of “parallelism”: If national authorities are not able to arrest suspects (Uganda) or investigate (Afghanistan), neither is the ICC. Complementarity does not address wider rule of law challenges, and in some cases, it allows for unfair trials on the domestic level, as was the case in Libya. The flaws of complementarity may inhibit the Court’s impact.

The ICC was meant to end impunity for the world’s worst crimes, thus contributing to their prevention. But twenty years after its establishment, its “theory of change” remains unclear, and few studies focus on its impact on the ground. To assess the Court’s impact, it is necessary to define the assumptions underlying its establishment. While deterrence is one such assumption, to date the evidence that the ICC effectively deters crimes is lacking. Other assumptions can be found in the Rome Statute itself, or in the expressed intentions of the Assembly of States Parties or senior officials of the Court. Lessons can also be drawn from impact studies of other international criminal tribunals. These sources indicate that the ICC should play an expressive function by engaging in norm projection. The chapter identifies four intended effects of the Rome Statute and ICC, including systemic effect on domestic legal systems; transformative effect on peace processes; reparative effect on victims; and demonstration effect, relating to its expressive function among affected communities. These four effects form an analytical framework to assess the impact of the ICC.

Chapter 3 further expands on systemic effect and argues that impact of the Rome Statute on domestic legal systems is better described as “internalization.” Internalization is the process whereby states demonstrate compliance with international law. The chapter examines internalization in Afghanistan, Colombia, Libya, and Uganda. Indicators of systemic effect, in the form of internalization, include implementation of domestic laws covering the Rome Statute crimes; the establishment of new or specialized investigative units or chambers to investigate or prosecute Rome Statute crime; or (genuine) national proceedings for Rome Statute crimes. The chapter concludes that “internalization” is taking place in all the countries under study. Laws have been amended, and new institutions established. National proceedings took place in all four countries. However, domestic proceedings in Colombia and Uganda demonstrate that it can be complex to assess for “genuineness.” In fact, most domestic proceedings are taking place in Colombia, a country with a robust legal system. This may mean that the Court has the most impact where it is needed the least.

This chapter analyses the various impacts international human rights law has on international criminal law. Through a careful analysis of the most emblematic cases of this interplay – from the case law of the ad hoc tribunals for the former Yugoslavia and Rwanda to the International Criminal Court, it shows that judicial application and interpretation of the Statutes of International Criminal Tribunals and Courts in light of human rights law had a systemic effect on international law. In particular, it formal as well as conceptual legal borrowing from IHRL has led to new interpretations of existing international criminal law; imposed procedural and substantive obligations onto the international criminal tribunals and courts; served as a gap-filler; and qualified existing law. In light of the contextual nuances of international criminal justice, the paper argues that many of the cases demonstrating the systemic effect of IHRL on ICL are not coherent applications of the principle of systemic integration.