Nicole Citeroni (University of Luxembourg)

1. On 22 January 2022, the European Court of Human Rights (ECtHR) delivered its judgment in the Milanković v. Croatia case, holding unanimously that the applicant’s convictions for war crimes based on command responsibility do not infringe on the prohibition of punishment without law under art. 7 of the Convention for the Protection of Human Rights and Fundamental Freedoms (“the Convention”).

Mr Vladimir Milanković, a Croatian national, had been charged before the Osijek County Court (Županijski sud u Osijeku) with twenty-two counts of war crimes committed against Serbian civilians in the period between mid-August 1991 and mid-June 1992. Seventeen war crimes against a civilian population and one war crime against a prisoner of war, had been allegedly committed by omission, i.e. by Milanković’s failure to prevent the police units under his command from perpetrating war crimes. He was held criminally liable for these offences on the basis of the principle of guarantor liability, and his convictions were upheld by the Croatian Supreme Court and the Constitutional Court. As a consequence, on 24 July 2020, he lodged an application against the Republic of Croatia with the ECtHR, claiming that his convictions for war crimes on the basis of command responsibility were in breach of art. 7 of the Convention.

The applicant contested the existence of a clear national or international legal basis for the application of command responsibility in non-international armed conflicts (NIACs). His argument relied on the absence of any reference to the doctrine of command responsibility in the Basic Criminal Code of Croatia (Osnovni krivični zakon Republike Hrvatske), whose blanket provisions generically referred to «rules of international law». The applicant maintained that those provisions could not be interpreted in light of the articles 86 and 87 of the First Protocol to the Geneva Conventions. Although this instrument expressly regulates the doctrine of command responsibility, it only applies to international armed conflicts (IACs). At the time in which war crimes were allegedly committed by the applicant, the declaration of independence of Croatia had not yet come into effect, meaning that the relevant crimes had been committed during a non-international armed conflict. However, the Second Protocol to the Geneva Conventions applicable to NIACs does not expressly provide for command responsibility. For this reason, the applicant claimed that, at the time of the commission of war crimes, no conventional rule of international law envisaged the applicability of the doctrine of command responsibility to internal armed conflicts.

As a consequence, the applicant claimed that he could not have foreseen the criminal character of his alleged conduct.

Other two arguments were raised by the applicant before the ECtHR. On the one hand, he held that he could not be convicted on the basis of the doctrine of command responsibility since most of the direct perpetrators had not been identified. They could have been members of other military, police, paramilitary or informal units, falling outside the scope of his responsibility. On the other hand, he argued that, as deputy head of the police department, he did not hold sufficient powers to be held criminally liable as a commander.

2. The First Section of the ECtHR declared Milanković’s application admissible, although it unanimously rejected the applicant’s arguments on two main grounds. To reach this conclusion, the Strasbourg Court reaffirmed fundamental principles laid down in its case-law on art. 7 of the Convention (Milanković v. Croatia, par. 50; see also Guide on Article 7 of the European Convention on Human Rights). Having regard to the objective of the principle of legality to «provide effective safeguards against arbitrary prosecution, conviction and punishment» (Del Río Prada v. Spain, par. 77; Kononov v. Latvia, par. 185; Vasiliauskas v. Lithuania, par. 153,), art. 7 of the Convention prohibits any retroactive application of criminal law and any interpretation of criminal law by analogy, while ensuring compliance with the nullum crimen, nulla poena sine lege principle, according to which a crime must be clearly defined in the law and penalties must be prescribed in the law. The term «law» is to be interpreted as including both national and international law (art. 7(1) of the Convention; Vasiliauskas v. Lithuania, par. 154), as well as both written and unwritten law (Vasiliauskas v. Lithuania, p. 154; Korbely v. Hungary, par. 70; Kononov v. Latvia, par. 185; Del Río Prada v. Spain, par. 115; Jorgic v. Germany, par. 100).

Against this background, the ECtHR’s reply to the first argument raised by the applicant comes from the definition itself of «rules of international law», which encompasses both conventional and customary rules. In this respect, the Court endorsed the approach adopted by the Trial Chamber of the ICTY in the Hadžihasanović and Others case, to state that the doctrine of command responsibility for war crimes perpetrated in NIACs was already established as a rule of customary international law in 1991 (Decision on Joint Challenge to Jurisdiction, 25 July 2003, par. 93 and 179). More specifically, command responsibility was part of customary international law even before the adoption of the aforementioned articles included in the First Protocol to the Geneva Conventions, which «were in this respect only declaring the existing position, and not constituting it» (Hadžihasanović and Others case, Appeals Chamber, Decision on Interlocutory Appeal Challenging Jurisdiction in Relation to Command Responsibility, 16 July 2003, par. 29). Likewise, art. 7(3) of the ICTY Statute on command responsibility, did not constitute new law but declared existing law under customary international law (see above Hadžihasanović and Others case, Trial Chamber, par. 179).

The ECtHR provided the applicant with a detailed explanation of the reasons underlying the customary international law status of command responsibility. The Court held that this status arises from the «essence of the command responsibility», which stems from the principle of responsible command (Milanković v. Croatia, par. 60). The latter implies duties and obligations, whose breach results in command responsibility. Therefore, the fil rouge connecting command responsibility to responsible command is the «guarantor obligation», i.e. a set of obligations and duties that are inherent in the commander’s professional activity (see André Nollkaemper, Harmen van der Wilt, p. 132). In the context of an armed conflict, those obligations derive from the relevant rules of international law «to protect the civilian population and prisoners of war from the acts prohibited by international humanitarian law and the law of war» (Milanković v. Croatia, par. 28).

A commander should then respect the guarantor obligation inherent in his or her activity, regardless of both the character of the armed conflict and his or her civilian or military status. The irrelevance of this status had been repeatedly emphasised during the military trials held in the aftermath of World War II. Neither the Charter of the International Military Tribunal, nor the Control Council Law no. 10, contained any reference to military commanders, but they generically referred to «superiors». Furthermore, the jurisprudence of these tribunals explicitly included civilians in the notion of «superiors» (see United States v Friedrich Flick and others case, Vol. VI; see also France v Roechlich case). This broad interpretation was then confirmed by the ad hoc tribunals (Delalić, Mucić et al. case, Trial Chamber Judgement, par. 333; Kayishema and Ruzindana, Trial Chamber Judgement, par. 213) by the International Red Cross in its Customary International Humanitarian Law study (rule 153); as well as by the International Criminal Court (ICC), whose statutory provision on command responsibility requires different conditions to be met in order to establish the responsibility of military commanders, on the one hand, or of civilian commanders, on the other one (art. 28 of the Rome Statute; see also Nora Karsten).

With respect to the foreseeability argument raised by the applicant, the ECtHR held that no judicial development of the doctrine of command responsibility can undermine the clarity of its legal basis, provided that such a development of the law was «consistent with the essence of the offence and could be foreseen» (Milanković v. Croatia, par. 59; see also Jorgic v. Germany, par. 101). In this respect, the ECtHR reaffirmed the principle whereby «in the context of a commanding officer and the laws and customs of war, the concepts of accessibility and foreseeability must be considered together» (Milanković v. Croatia, par. 62). Hence, the Court did not carefully analysed the accessibility element, although – by drawing upon the ICTY jurisprudence – it noted that even laws based on customs can be considered as «accessible» (see above Hadžihasanović and Others case, Appeals Chamber, par. 34).

As to the foreseeability requirement, the ECtHR referred to the interpretation of this concept elaborated in the Kononov v. Latvia case. Unlike Milanković, Kononov was a military commander accused of having perpetrated war crimes against civilians in Latvia in 1944. Todismiss the applicant’s claim that the criminal character of the impugned acts could not be foreseen, the Court reiterated the well-established principle that foreseeability «depends to a considerable degree on the content of the instrument in issue, the field it is designed to cover and the number and status of those to whom it is addressed» (Kononov v. Latvia, par. 235). It also added that when it comes to professionals, the degree of diligence in carrying on a professional activity should be higher than usual and should be accompanied by a special assessment of the risks entailed by that activity (see Pessino v. France , par. 33; Vasiliauskas v. Lithuania, par. 157). Moreover, aligning its position with the jurisprudence of the ICTY, in the Milanković v. Croatia case the ECtHR established that for the purpose of proving the foreseeability of a crime and of its consequences, it is necessary to consider the ability of the applicant to appreciate that,at the relevant time, the conduct was criminal «in the sense generally understood, without reference to any specific provision» (see above Hadžihasanović and Others case, Appeals Chamber, par. 34). If the second part of this finding – «without reference to any specific provision» – is in line with the ECtHR’s case-law stating that a crime can be defined not only by written but also by unwritten law, the meaning of the first part – «the conduct is criminal in the sense generally understood» – is vague. It is generally agreed that the criminal character of particularly serious offences, such as war crimes, can be foreseen by their nature (see Alexander Skander Galand, p. 145). This is why the ECtHR inferred not only from the applicant’s professional activity but also from the «flagrant unlawful nature of the war crimes committed by the police units» under Milanković’s command, the ability of the applicant to appreciate that the acts were criminal and that failure on his part to prevent or punish those acts would have breached his guarantor obligations, and entailed his criminal liability on the basis of command responsibility. The same argument had already been held in the Šimšić case by the fourth section of the ECtHR. The Court had found that, considering the professional activity of the applicant – he was a police officer – and the unlawful nature of the acts committed in the context of a widespread and systematic attack directed against the Bosniac civilian population, he should have foreseen that those acts constituted crimes against humanity for which he could have been held criminally responsible (Šimšić v. Bosnia and Herzegovina, par. 24). As a result of the foregoing arguments, the ECtHR concluded that Milanković’s conviction based on the doctrine of command responsibility, i.e. on a rule of customary international law, fully complied with the foreseeability and accessibility requirements of the legality principle.

As to the third and fourth arguments, which concerned questions of fact, the ECtHR restated the general rule that the factual assessment of a case is carried out by domestic courts and binds the Court, unless there exist «cogent elements to lead it to depart from the findings of fact reached by those courts» (Milanković v. Croatia, par. 68). In the Radomilja and Others v. Croatia case, the ECtHR had already emphasised its subsidiary role in the assessment of factual circumstances, which should be appreciated by national courts (Radomilja and Others v. Croatia, par. 150).

In the Milanković v. Croatia case,the Strasbourg Court upheld the Croatian courts’ finding that the applicant, as deputy head of the police department, had sufficient formal and actual command authority over the police units that committed war crimes, and that he knew or had been aware of those crimes. With respect to the other argument raised by the applicant, evidence examined by domestic courts suggested that war crimes had been committed by members of the police units under the applicant’s command, even though some of the direct perpetrators could not be identified. This is in line with judicial developments on the doctrine of command responsibility. The ICTY held on several occasions that the identification of the alleged direct perpetrators is fundamental to establish the existence of a superior-subordinate relationship, although it is sufficient to identify the group to which the subordinate belonged and to prove that the superior could effectively exercise his or her authority over the group (Blaškić case, Appeals Chamber Judgement, par. 217; see above André Nollkaemper, Harmen van der Wilt, p. 186).

3. It results from the above that the relevance of the Milanković v. Croatia judgment lies essentially in two findings set forth by international criminal tribunals and reiterated by the ECtHR.

The first finding is that any criminal conviction based on command responsibility has a sufficiently clear legal basis in international law, sincethe applicability of the doctrine of command responsibility in both international and internal armed conflicts is a well-established rule of customary international law (par. 60-61 Milanković v. Croatia). The customary international law status of command responsibility in both IACs and NIACs has crystallised over the years in the jurisprudence of the ad hoc Criminal Tribunals (see Brđanin case, Trial Chamber Judgement, par. 275; Strugar case, Trial Chamber Judgement, par. 357; Akayesu case, Trial Chamber Judgement, par. 612-613) and of the Special Court for Sierra Leone (SCSL), which addressed the question of «whether superior responsibility could serve as a proper basis for conviction in internal armed conflicts» (see Harmen van der Wilt, p. 144). In the Prosecutor v. Norman case, the SCSL followed the ICTY’s finding, holding that the application of command responsibility in internal armed conflicts was already part of international humanitarian law at the time relevant for the indictment (Decision on the Defense Preliminary Motion on Lack of Jurisdiction: Command Responsibility, 15 October 2003, para. 24). Likewise, the ECtHR case-law (see Kononov v. Latvia, par.211), as well as prominent scholars (see Kai Ambos; Chantal Meloni; Jamie Allan Williamson), confirmed the consolidated customary status of command responsibility in NIACs.

The second finding is related to the former. Convictions based on rules of customary international law do not infringe on the principle of legality, provided that those rules are accessible and foreseeable by the accused tempore criminis.

4. More generally, the most obvious observations emerging from the Milanković v. Croatia case is that the ECtHR correctly interpreted the principle of legality in conformity with public international law, international criminal law, and human rights law.

First, the Court endorsed an interpretation of the principle of legality that, on the one hand, fully respects the purpose of this essential element of the rule of law and, on the other, significantly ensures continuity and consistency with its own established case-law on art. 7(1) of the Convention. Notably, the legal arguments elaborated by the Court confirmed the relevance of customary international law as a long-standing source of law and criminal responsibilitywithin the meaning of art. 7(1) of the Convention. Therefore, it was not necessary to assess whether the applicant’s convictions had a legal basis in art. 7(2) of the Convention, since the Court assesses the existence of «general principles of law recognised by civilised nations» only when a national or international “law” – providing for the criminal character of a conduct – did not exist at the relevant moment. In the case at hand, the Court clearly established that, at the relevant material time, the applicant’s convictions for war crimes were legally justified by a rule of international law.

Secondly, the Court reaffirmed the most important principles developed by international criminal tribunals – in particular by the ICTY – on the applicability of the doctrine of command responsibility in both IACs and NIACs. International jurisprudence and scholars have upheld that convictions based on rules of customary law are in line with the legality principle if the requirements of foreseeability and accessibility are satisfied (see Yudan Tan, p. 94). Among the ICTY cases enhancing the view that customary rules are sources of criminal law and responsibility is the above mentioned Hadžihasanović and Others case, with respect to the applicability of command responsibility in NIACs. Moreover, the drafters of the Rome Statute made a significant step further, by including an – implicit – reference to customary law under para. (b) of art. 21, which lists the sources of law that the ICC can apply (see Schabas, p. 383-85; Degan, p. 52).