In May 1960, Israeli Mossad agents infiltrated Buenos Aires and kidnapped Adolf Eichmann, a former Nazi SS lieutenant colonel who was among the chief architects of the Holocaust. From there, they transported him to Jerusalem, where he stood trial, was convicted, and was executed, for genocide, crimes against humanity, and war crimes. The Eichmann trial is a striking example of international criminal law—the prosecution of a German national by the State of Israel (which was not founded as a nation until May 1948, years after WWII had ended) for crimes he committed against the Jewish people (of which Polish, Soviet, and Hungarian Jews formed the largest group of victims) after exfiltrating him from Argentina (in clear violation of its national sovereignty and legal jurisdiction). Here the conventional rules of domestic criminal law clearly do not apply. And yet, it can hardly be debated, the interests of justice were nonetheless served. The magnitude and gravity of Eichmann’s crimes necessitated that he stand trial, irrespective of any clearly delineated national jurisdiction. If Germany or Argentina could not—or would not—prosecute him, then Israel would. The implicit assumption underpinning the Eichmann trial, and international criminal law as a whole, is that certain crimes are so egregious that justice demands they be prosecuted, if not under domestic criminal law and by a domestic court, then under international criminal law by an international court or tribunal. 

The role of international criminal law may be clarified by placing it in its legal context. Three primary legal regimes exist for crimes which cross national borders: 1) transnational criminal law, which concerns any part of domestic criminal law that regulates cross border events or actions; 2) treaty-based domestic law, which concerns actions or events that are criminalized under international treaties but enforced under the domestic law of treaty-parties; and 3) international criminal law in the strict sense, which concerns “core crimes” that are criminalized under international law whether or not they are criminalized under domestic law.¹ These core crimes include war crimes, crimes against humanity, genocide, and the crime of aggression—namely, jus cogens, the prohibition of which may be considered an erga omnes obligation. The perpetration of such egregious crimes is, therefore, considered “an offence not merely against the State directly affected by [their] breach, but also against all members of the international community,” and one state’s failure to prosecute jus cogens breaches under domestic law is a failure of justice with universal implications.² 

International criminal law does not, then, merely add to domestic criminal law, but in one sense it transcends domestic criminal law. For example, although a territorial state may have no domestic legislation criminalizing war crimes, it is nonetheless bound by jus cogens, which insist that war crimes be criminalized, and the absence of relevant domestic legislation provides the state no justification for its failure to prosecute. Furthermore, should a state prove itself unable or unwilling to do so, prosecutorial jurisdiction will fall either to the relevant international judicial body, as per treaty-law, or become universal. Thus, under the principle of universal jurisdiction, “a state may exercise prescriptive jurisdiction with respect to offenses widely considered by states as being of universal concern… even if it has no specific connection to the perpetrator, the victim, or the place where the offense occurred.”³ While universal jurisdiction is rare in practice, due to significant controversy, it nonetheless exemplifies the supranational nature of international criminal law.  

It may thus be suggested that international criminal law has a fundamentally negative existence—it fills the void left by domestic criminal law. Often, core crimes “cannot effectively be prosecuted or repressed by the territorial state where they are committed, either because the state itself has perpetrated them or because the its government has collapsed in civil war, anarchy, or through foreign conquest.”⁴ For example, in 2009-10, the International Criminal Court (ICC) issued arrest warrants for Sudanese President Omar Al Bashir for crimes against humanity, war crimes, and genocide. Under Bashir’s government, the state of Sudan not only armed Arab janjaweed militias to fight against African rebels, but also empowered these militias to kill as many as 200,000 people and displace 2.3 million others. In the face of such atrocities, domestic criminal law was powerless, as the ruling government was itself responsible for the atrocities. Domestic law had, in effect, left a judicial void which international criminal law filled. The fundamental principles of justice necessitated that such egregious crimes be prosecuted, and since the Sudanese government was unable (and, indeed, unwilling) to prosecute itself, the responsibility was taken up by the ICC. 

International criminal law also allows the interests of justice to prevail where domestic law might otherwise succumb to political interests. This was particularly illustrated after the conclusion of WWII. Following the defeat of the European Axis powers in September 1945, the Allies discussed how to best punish members of the German leadership for their war crimes. Britain proposed those most responsible “face summary execution on the basis of purely political decisions.”⁵ The Soviet government suggested the guilt of the German leadership be politically determined, but that both their degree of guilt and their sentences be determined in international trials. Under the moderating influence of the United States, however, the Allies ultimately chose to establish an international military tribunal in Nuremberg, where German war criminals would be tried and sentenced under the presumption of innocence. In his opening statement to the Court, chief prosecutor Robert Jackson stated, “That four great nations, flushed with victory and stung with injury, stay the hands of vengeance and voluntarily submit their captive enemies to the judgement of the law, is one of the most significant tributes that Power has ever paid to Reason.”⁶ Rather than succumbing to the siren call of vindictive victor’s justice, through Nuremberg the Allied powers allowed hot-blooded emotion to give way to the blind scales of justice. International criminal law thus evolved from domestic criminal law’s inability to impartially adjudicate over heinous breaches of jus cogens committed against one state by another state’s actors. 

International criminal law is necessary, therefore, because situations exist in which domestic criminal law is insufficient to effectively prosecute crimes which must be prosecuted—whether because the state is itself the perpetrator, or because the state is materially unable to prosecute due to civil war, lawlessness, or conquest. Thus, “international criminal law in the strict sense is a product of discontinuity, of upheaval and political rupture.”⁷ It exists in the void created by the failure or absence of domestic criminal law. This is not to suggest, however, that international criminal law is not also prone to failure. It is an imperfect mechanism with significant limitations (as critics of the ICC make clear). It further lacks an internal enforcement mechanism to enact its own judgements. Even so, to repeat the words of Robert Jackson, it stands as “one of the most significant tributes that Power has ever paid to Reason.” Moral law insists that egregious crimes be met with justice, regardless of place, perpetrator, or victim. International criminal law is the mechanism by which that justice is meted when domestic law falls short. 

^{1 David Luban, Julie R. O’Sullivan, and David P. Stewart, International and Transnational Criminal Law, 3rd ed. (New York: Wolters Kluwer Law & Business, 2014), 3-5.
2 Alexander Orakhelashvili, Akehurt’s Modern Introduction to International Law, 8th ed. (New York: Routledge, 2018), 55. 
3 Luban, International and Transnational Criminal Law, 213.
4 Ibid., 4.
5  bid., 76.
6 Robert Jackson, “Opening Statement,” The Trial of German Major War Criminals by the International Military Tribunal Sitting at Nuremberg. Volume II. Proceedings: 11/14/1945-11/30/1945.
7 Luban, International and Transnational Criminal Law, 18.} 

Sources

• Jackson, Robert. “Opening Statement.” The Trial of German Major War Criminals by the International Military Tribunal Sitting at Nuremberg. Volume II. Proceedings: 11/14/1945-11/30/1945.
• Luban, David, Julie R. O’Sullivan, and David P. Stewart. International and Transnational Criminal Law. Third edition. New York: Wolters Kluwer Law & Business, 2018.
• Orakhelashvili, Alexander. Akehurt’s Modern Introduction to International Law. Eighth Edition. New York: Routledge, 2018.  
• Snyder, Timothy. Bloodlands: Europe Between Hitler and Stalin. New York: Basic Books, 2010.