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.