THE PRINCIPLE OF COMPLEMENTARITY BETWEEN INTERNATIONAL AND DOMESTIC JURISDICTIONS IN THE PROSECUTION OF WAR CRIMES
##plugins.themes.bootstrap3.article.main##
##plugins.themes.bootstrap3.article.sidebar##
Abstract
The article reconstructs the legal architecture of complementarity under the Rome Statute and articulates the ICC’s admissibility tests: unwillingness (shielding, unwarranted delay, lack of independence/impartiality), inability (total or substantial collapse/ unavailability of the national system), gravity, and the “same person/same conduct” standard. Drawing on Ongwen, Ruto and the Libya decisions (Saif Al-Islam Gaddafi; Al-Senussi), it distils how the Court distinguishes declaratory reforms from genuine investigative and prosecutorial action, assesses the availability of the accused, and evaluates a state’s capacity to secure a fair trial. A comparative institutional section demonstrates models from Nuremberg/Tokyo (exclusive jurisdiction over “major war criminals”), through ICTY/ICTR (tribunal primacy over national courts), to hybrid tribunals (SCSL, ECCC, Kosovo SC), situating the ICC’s contemporary role as complementing—rather than replacing—domestic justice. Focusing on Ukraine’s wartime context, the paper identifies admissibility risks (in absentia trials, use of pre-trial statements, special evidentiary rules) and proposes safeguards that demonstrate the genuineness and capacity of domestic proceedings (comprehensive audio-video recording, effective defence and cross-examination, reasoned judgments and proportionality of sanctions). It develops a practical algorithm for delineating jurisdictions and distributing criminal proceedings among national courts, the ICC, and possible hybrid mechanisms, taking into account the preconditions and triggers of jurisdiction, the admissibility tests (Article 17 of the Rome Statute), the “same person/same conduct” standard, and the “gravity” criterion. A roadmap for positive (proactive) complementarity is offered for Ukraine—capacity-building, harmonised evidence standards, structured cooperation with the ICC Office of the Prosecutor, and duplication-minimising protocols. The contribution lies in integrating the ICC’s admissibility doctrine with wartime procedural realities, clarifying terminology (primacy vs. “parallelism”), and introducing operational metrics of genuineness/capacity for oversight. The practical significance consists in developing policy tools for the prosecution of war crimes that are compatible with complementarity and fair-trial guarantees.
How to Cite
##plugins.themes.bootstrap3.article.details##
principle of complementarity, admissibility, unwillingness, inability, gravity, same person/same conduct, International Criminal Court, ICTY/ICTR primacy, hybrid tribunals, positive complementarity, Ukraine, war crimes
Sprav tysiachi of the International Criminal Court. (1998). Available at: https://www.icc-cpi.int/resource-library/Documents/RS-Eng.pdf
Bysaha, Yu. M., Bielov, D. M., & Berch, V. V. (et al.). (Ed.). (2023). Law in wartime: issues of theory and practice. Uzhgorod: Yashchenko Yevhen Valeriiovych.
The crimes were committed during the period of full-scale Russian invasion. Prosecutor General's Office. Available at: https://www.gp.gov.ua/
United Nations General Assembly Resolution A/RES/ES-11/6. (n.d.). docs.un.org. Available at: https://docs.un.org/a/RES/ES-11/6
Thousands of cases, but many times fewer convictions. How war crimes are investigated in Ukraine. (n.d.). https://www.helsinki.org.ua. Available at: https://www.helsinki.org.ua/articles/sprav-tysiachi-ale-vyrokiv-v-razy-menshe-yak-rozsliduiut-voienni-zlochyny-v-ukraini/
Koruts, U. Z. (2023). Investigation by the International Criminal Court into Russian war crimes in Ukraine. Academic Notes of the V.I. Vernadsky TNU. Series: Legal Sciences, 1, 34(73). Available at: https://juris.vernadskyjournals.in.ua/journals/2023/2_2023/28.pdf
Situation in Uganda: The Prosecutor v. Dominic Ongwen (2021). International Criminal Court. Available at: https://www.icc-cpi.int/case/uganda/dominic-ongwen
Prosecutor v. Saif Al-Islam Gaddafi and Abdullah Al-Senussi (2013). International Criminal Court. Available at: https://www.icc-cpi.int/case/libya
Judgment of the International Military Tribunal for the Trial of German Major War Criminals (1946). (n.d.). https://www.loc.gov. Available at: https://www.loc.gov/rr/frd/Military_Law/Nuremberg.html
Charter of the International Military Tribunal for the Far East (1946). (n.d.). https://www.un.org. Available at: https://www.un.org/en/genocideprevention/documents/atrocity-crimes/Doc.2_Tokyo%20Charter.pdf
Ambos, K. (2015). Treatise on International Criminal Law: The Crimes and Sentencing. Journal of International Criminal Justice, 13(2), 409-411.
Schabas, W. A. (2016). The International Criminal Court: A Commentary on the Rome Statute. Oxford: Oxford University Press.
Heller, K. (2012). A sentence-based theory of complementarity. Harvard international law journal, 53(1), 201-249.
Burke-White, W. W. (2008). Proactive Complementarity: the International Criminal Court and National Courts in the Rome System of International Justice. Harvard International Law Journal, 49(1), 66-67.
El Zeidy, M. M., & El Zeidy, M. M. (2002). The Principle of Complementarity: A New Machinery to Implement International Criminal Law. Michigan Journal of International Law, 23. Available at: https://repository.law.umich.edu/mjil/vol23/iss4/3/
Smyrnov, M. (2024). The procedure for cooperation between Ukraine and the International Criminal Court. Dnipro Scientific Journal of Public Administration, Psychology, and Law, 4, 116-120.
Kaplii, O., & Smoliar, Yu. (2024). Legal principles of interaction between the International Criminal Court and Ukraine. Scientific Bulletin of Kherson State University. Series "Legal Sciences", 6, 29-35.
Udovenko, Zh. (2024). Peculiarities of cooperation between the competent authorities of Ukraine and the International Criminal Court. European Law Journal, 2, 97-101.
Plakhotnik, O. (2022). Cooperation of the Prosecutor's Office of Ukraine with the International Criminal Court. Bulletin of the Taras Shevchenko National University of Kyiv. Series "Legal Sciences", 3, 56-63.
Pimenova, A., & Kuzmenko, V. (2024). Problematic issues and prospects of Ukraine's participation in the implementation of international criminal justice. Scientific Bulletin of Uzhhorod National University. Series "Law", 82(3), 235-242.
Kleffner, J. (2008). Complementarity in the Rome Statute and National Criminal Jurisdictions. Oxford: Oxford University Press.
Clapham, E. (2003). Issues of Complexity, Complicity and Complementarity: From the Nuremberg Trials to the Dawn of the New International Criminal Court. From Nuremberg to The Hague. The Future of International Criminal Justice (pp. 20-67). Р. Sands (Ed.). Cambridge.
Popko, V. V. (2019). The principle of complementarity in international criminal law. Current problems of the state and law, 82. Available at: http://apdp.onua.edu.ua/index.php/apdp/article/view/17
Policy Paper on Preliminary Examinations. (2013). Office of the Prosecutor, International Criminal Court. Available at: https://www.icc-cpi.int/sites/default/files/otppolicy-pe-Eng.pdf
Making Justice Count: Lessons from the ICC’s Early Years on Complementarity. (2021). Human Rights Watch. Available at: https://www.hrw.org/report/2021/04/19/making-justice-count
Stigen, J. (2008). The Relationship between the International Criminal Court and National Jurisdictions: The Principle of Complementarity. Martinus Nijhoff Publishers.
Prosecutor v. Germain: Policy Paper on Complementarity. ICC-OTP (2023). International Criminal Court. Available at: https://www.icc-cpi.int/resources/otp-policy-complementarity
Prosecutor v. Germain Katanga (2014). Judgment of the Appeals Chamber. ICC-01/04-01/07. Available at: https://www.icc-cpi.int/case/katanga
Ambos, K., & Wirth, S. (2020). The Principle of Complementarity in Practice. Criminal Law Forum, 31(3), 295-322.
Prosecutor v. Bosco Ntaganda. (2021). Judgment on the Appeals Chamber. ICC-01/04-02/06 A2. Available at: https://www.icc-cpi.int/case/ntaganda
Prosecutor v. Ahmad Al Faqi Al Mahdi. (2016). Judgment and Sentence. ICC-01/12-01/15. Available at: https://www.icc-cpi.int/case/almadhi
Prosecutor v. Thomas Lubanga Dyilo. (2014). Judgment on the Appeal of the Prosecutor. ICC-01/04-01/06 A5. Available at: https://www.icc-cpi.int/case/lubanga
Establishment of a Special Tribunal for the Crime of Aggression against Ukraine: Concept Note and Legal Framework. (2023). Council of Europe. Available at: https://www.coe.int/en/web/portal/ukraine-special-tribunal
Complementarity and Cooperation. (2013). Policy Paper on Preliminary Examinations. The Office of the Prosecutor. International Criminal Court. Available at: https://www.icc-cpi.int/sites/default/files/otppolicy-pe-Eng.pdf
Agreement between Ukraine and the Council of Europe on the Establishment of a Special Tribunal for the Crime of Aggression against Ukraine. (2025) (n.d.). zakon.rada.gov.ua. Available at: https://zakon.rada.gov.ua/laws/show/994_002-25#Text. [in Ukrainian].
The Prosecutor v. Saif Al-Islam Gaddafi, ICC-01/11-01/11. (2022). (n.d.). www.icc-cpi.int. Available at: https://www.icc-cpi.int/sites/default/files/2022-08/GaddafiEng.pdf.
Murphy, S. (2021). The future of complementarity in international criminal justice. Harvard International Law Journal, 62(2), 267-309.
The Case of the Prosecutor v. William Samoei Ruto, Henry Kiprono Kosgey and Joshua Arap Sang, ICC-01/09-01/11 (2012). Available at: https://www.icc-cpi.int/sites/default/files/CourtRecords/CR2012_02389.PDF
This work is licensed under a Creative Commons Attribution 4.0 International License.