155. Relying on the Appeals Chamber Judgements in Orić and Blaškić, Šljivančanin submits that, at a minimum, aiding and abetting by omission requires an elevated degree of “concrete influence”.[1] He argues that this provides an objective standard for establishing whether his omission had a “substantial effect” on the mistreatment of prisoners[2] and that the contribution must be considered from the perspective of the perpetrators of the crime, not the omission itself.[3] Šljivančanin also appears to propose that the failure to act must have a “decisive effect” on the commission of the crime,[4] but fails to elaborate this point. The Prosecution responds that there is no indication that the “concrete influence” standard is in fact any higher than “substantial effect” which is the correct standard,[5] and that Šljivančanin’s reliance on the Orić case is misplaced, since in that case the Appeals Chamber used the term “concrete influence” in the context of its finding that aiding and abetting by omission requires more than a simple correlation between the omission and the crimes.[6] The Prosecution submits that to prove that an omission had a substantial effect on the crime, it must be shown that the crime would have been substantially less likely to have occurred had the accused acted.[7]

156. The Appeals Chamber recalls that, in the Orić case, it found that the actus reus for “commission by omission requires an elevated degree of ‘concrete influence’”,[8] as distinct from the actus reus for aiding and abetting by omission, the latter requiring that the omission had a “substantial effect” upon the perpetration of the crime.[9] The Appeals Chamber finds no merit in Šljivančanin’s attempt to conflate the substantial contribution requirement with the notion of an elevated degree of influence,[10] and notes that Šljivančanin himself does not provide any further support for his submission on this issue, beyond the vague statement that an “objective criteria” for assessing “substantial contribution” is warranted on the particular facts of his case.[11] Accordingly, Šljivančanin’s argument is dismissed.

1677. The Appeals Chamber recalls that a person may be held criminally responsible for aiding and abetting by omission where he or she fails to discharge a legal duty and by this failure assists, encourages or lends moral support to the perpetration of a crime and has a substantial effect on the commission of that crime.[1] Additionally, aiding and abetting by omission necessarily requires that the accused has “the ability to act, or in other words, that there were means available to the accused to fulfil this duty”.[2]

1678. The Appeals Chamber considers that while Lazarević’s failure to take investigative and punitive measures against the commission of forcible displacement may have had an effect on the ability of the military prosecutor to pursue perpetrators of such crimes, this in itself is not conclusive for the purposes of establishing aiding and abetting liability. Rather as recalled above, in order to fulfil the actus reus of aiding and abetting, it must be demonstrated that any such omission substantially contributed to the continued commission of forcible displacement.[3] […]

146.  […] The Appeals Chamber is also not convinced that the Trial Chamber was specifically required to determine that assailants of the Night and Day Attacks heard what he said at the Cyayi centre. The Appeals Chamber recalls that the actus reus of “instigating” is to prompt another person to commit an offence.[1] It is not necessary to prove that the crime would not have been perpetrated without the involvement of the accused; it is sufficient to demonstrate that the instigation was a factor substantially contributing to the conduct of another person committing the crime.[2] Similarly, it is not required that the individuals who were instigated be the same as those who committed the crimes.[3]