The twenty-first century has seen no shortage of international criminals. In Eastern Europe, the Russian army has committed war crimes, as evidenced by the mass graves unearthed by the Ukrainian army. Elsewhere, repressive governments continue their relentless persecution of minorities. Though not to the same magnitude as the twentieth century, the twenty-first century reminds us that sovereign nations are often the most willing perpetrators of international crimes. As countries continue to renounce the international order, the inability of the global community to prosecute international crimes has become increasingly apparent.
Modern international criminal law—codified in the Rome Statute of 2002—outlines four international crimes: genocide, crimes against humanity, war crimes, and crimes of aggression. The Statute grants subject-matter jurisdiction over these crimes to the International Criminal Court (“ICC”). The ICC exists as a court of last resort, where heads of state and high-ranking government officials (whom domestic courts will not prosecute) can be held accountable for their crimes. The ICC’s territorial jurisdiction includes states that are parties to the Rome Statute or have otherwise accepted its jurisdiction. Its authority can extend to non-member states when a member of the United Nations Security Council refers the state to the ICC, though referral risks being vetoed by permanent Security Council members.
Despite its rigid framework, the ICC faces numerous limitations to successfully prosecuting international criminals. First, it suffers crises of legitimacy. Critics maintain that the ICC is a neocolonial tool for the West to target disfavored African leaders. This criticism is supported by the ICC’s seeming unwillingness to prosecute Western criminals. Indeed, of the eleven defendants the ICC has charged, ten have been African. Equally delegitimizing is the ICC’s lack of universal recognition. While the UN has 193 member states, only 123 countries are party to the Rome Statute. Two permanent (and arguably most powerful) members of the United Nations Security Council—the United States and China—never ratified the Rome Statute. Russia similarly withdrew from the Statute in 2016 after the ICC opened an investigation into its occupation of Crimea.
Second, international criminal prosecution within the ICC relies on state cooperation. That is, the ICC has no enforcement power against states that reject or withdraw from its jurisdiction. Syria, for instance, is not a party to the Rome Statute. Although a member of the Security Council could refer Syria’s war crimes to the ICC, its ally Russia, as a permanent member of the UN Security Council, is likely to veto any referral. Now, because of Russia’s withdrawal from the Rome Statute, it and Syria (among many other states) remain practically immunized from international criminal prosecution.
Although little can be done to compel state cooperation, countries can take other steps to strengthen the likelihood that alleged international criminals are prosecuted. States who are victims of international crimes can advocate for the United Nations to establish ad hoc tribunals. Under international law, ad hoc tribunals have jurisdiction over national courts, thereby removing the need for state cooperation. Noteworthy examples, like the Nuremberg and Yugoslav tribunals, proved effective at prosecuting war criminals even as recently as 2017. And importantly, ad hoc tribunals are impermanent and aim to prosecute crimes arising out of a single country or conflict. Because ad hoc tribunals are narrow in scope, unlike the ICC, they encounter less accusations of prejudice.
It is not too late for countries to recognize the ICC’s jurisdiction or assist with its efforts. Countries like the United States could lend significant legitimacy to the ICC by signing (or, to a greater degree, ratifying) the Rome Statute. Non-signatories to the Rome Statute, moreover, could support the ICC by protecting witnesses and avoiding non-essential contact with ICC fugitives. These initiatives, though mostly symbolic, reinforce countries’ commitment to engaging and preserving the rule of law in the global sphere. For its many faults, modern international criminal law—and its enforcement apparatus—is critical to meeting the challenges of the twenty-first century.
David Arras is a second-year law student at the University of Denver Sturm College of Law and Staff Editor on the Denver Journal of International Law and Policy.
 See Oona Hathaway, A Crime in Search of a Court, Foreign Affairs (May 19, 2022), https://www.foreignaffairs.com/articles/ukraine/2022-05-19/crime-search-court.
 Genocide Watch, People’s Republic of China, (Sep. 1, 2021), https://www.genocidewatch.com//country-pages/people’s-republic-of-china; Genocide Watch, Myanmar, (Jul. 16, 2021), https://www.genocidewatch.com/country-pages/myanmar%2Fburma.
 See Hathaway, supra note 1.
 International Criminal Court, Understanding the International Criminal Court at 9 (2020), https://www.icc-cpi.int/sites/default/files/Publications/understanding-the-icc.pdf.
 Matt Killingsworth, Justice, Syria, and the International Criminal Court, Australian Outlook (Dec. 24, 2019), https://www.internationalaffairs.org.au/australianoutlook/justice-syria-international-criminal-court/.
 Rome Statute of the International Criminal Court art. 12, Jul. 17, 1998, available at https://www.icc-cpi.int/sites/default/files/RS-Eng.pdf.
 Security Council Report, In Hindsight: The Security Council and the International Criminal Court (Jul. 31, 2018), https://www.securitycouncilreport.org/monthly-forecast/2018-08/in_hindsight_the_security_council_and_the_international_criminal_court.php.
 See Christa-Gaye Kerr, Sovereign Immunity, the AU, and the ICC: Legitimacy Undermined, 41 Mich. J. Int’l L. 195, 196 (2020).
 Kip Hale, ICC on Trial, Foreign Affairs (Dec. 11, 2014), https://www.foreignaffairs.com/articles/kenya/2014-12-11/icc-trial.
 Kerr, supra note 10.
 United Nations, About Us, https://www.un.org/en/about-us; Claire Klobucista, The Role of the International Criminal Court, Council on Foreign Relations (Mar. 28, 2022), https://www.cfr.org/backgrounder/role-international-criminal-court.
  See International Criminal Court, The State Parties to the Rome Statute, https://asp.icc-cpi.int/states-parties.
 Robbie Gramer, Why Russia just withdrew from the ICC, Foreign Policy (Nov. 16, 2016), https://foreignpolicy.com/2016/11/16/why-russia-just-withdrew-from-icc-putin-treaty-ukraine-law/.
 See Mona Yacoubian, Assad Is Here to Stay, Foreign Affairs (Jan. 25, 2022), https://www.foreignaffairs.com/articles/middle-east/2022-01-25/assad-here-stay.
 See Yacoubian, supra note 17.
 Hathaway, supra note 1.
 See Dan Zhu, China, The International Criminal Court, And Global Governance, Australian Outlook (Jan. 10, 2020), https://www.internationalaffairs.org.au/australianoutlook/china-the-international-criminal-court-and-global-governance/.
 Emma Daly, Beyond Justice: How the Yugoslav Tribunal Made History, Human Rights Watch (Dec. 19, 2017), https://www.hrw.org/news/2017/12/19/beyond-justice-how-yugoslav-tribunal-made-history. The Yugoslav Tribunal formally closed on December 21, 2017. Id.
 See Legal Information Institute, International Criminal Tribunals, https://www.law.cornell.edu/wex/international_criminal_tribunals.
 See Owen Bowcott, Yugoslavia tribunal closes, leaving a powerful legacy of war crimes justice, The Guardian (Dec. 20, 2017), https://www.theguardian.com/law/2017/dec/20/former-yugoslavia-war-crimes-tribunal-leaves-powerful-legacy-milosevic-karadzic-mladic.
 See Coalition for the International Criminal Court, 10 ways states can support the ICC and global justice, https://www.coalitionfortheicc.org/10-ways-states-can-support-icc-and-global-justice.
 See Stuart Ford, The Biden Administration Should Engage with the ICC—the Evidence Shows That It Saves Lives, Just Security (Jan. 28, 2021), https://www.justsecurity.org/74337/the-biden-administration-should-engage-with-the-icc-the-evidence-shows-that-it-saves-lives/.