47. The right of an accused to be tried before an impartial tribunal is an integral component of his right to a fair trial as provided in Articles 19 and 20 of the Statute.[1] Furthermore, Article 12 of the Statute cites impartiality as one of the essential qualities of any Tribunal Judge, while Rule 14(A) of the Rules provides that, before taking up his duties, each Judge shall make a solemn declaration that he will perform his duties and exercise his powers “impartially and conscientiously”. The requirement of impartiality is again recalled in Rule 15(A) of the Rules, which provides that “[a] judge may not sit in any case in which he has a personal interest or concerning which he has or has had any association which might affect his impartiality”.

48. The Appeals Chamber reiterates that there is a presumption of impartiality which attaches to any Judge of the Tribunal and which cannot be easily rebutted.[2] In the absence of evidence to the contrary, it must be assumed that the Judges “can disabuse their minds of any irrelevant personal beliefs or predispositions”.[3] Therefore, it is for the appellant doubting the impartiality of a Judge to adduce reliable and sufficient evidence to the Appeals Chamber to rebut this presumption of impartiality.[4]  [See also para. 183 of the Appeal Judgement]

49. In the Akayesu Appeal Judgement, the Appeals Chamber recalled the criteria set out by the ICTY Appeals Chamber regarding the obligation of impartiality incumbent upon a Judge:

That there is a general rule that a Judge should not only be subjectively free from bias, but also that there should be nothing in the surrounding circumstances which objectively gives rise to an appearance of bias. On this basis, the Appeals Chamber considers that the following principles should direct it in interpreting and applying the impartiality requirement of the Statute:

A. A Judge is not impartial if it is shown that actual bias exists.

B. There is an unacceptable appearance of bias if:

(i) a Judge is a party to the case, or has a financial or proprietary interest in the outcome of a case, or if the Judge’s decision will lead to the promotion of a cause in which he or she is involved, together with one of the parties. Under these circumstances, a Judge’s disqualification from the case is automatic; or

(ii) the circumstances would lead a reasonable observer, properly informed, to reasonably apprehend bias.[5]

50. The test of the reasonable observer, properly informed, refers to “an informed person, with knowledge of all the relevant circumstances, including the traditions of integrity and impartiality, apprised also of the fact that impartiality is one of the duties that Judges swear to uphold”.[6] The Appeals Chamber must therefore determine whether such a hypothetical fair-minded observer, acting in good faith, would accept that a Judge might not bring an impartial and unprejudiced mind to the issues arising in the case.[7]

78. The Appeals Chamber recalls that the Judges of this Tribunal and those of the ICTY are sometimes involved in several trials which, by their very nature, cover issues that overlap. It is assumed, in the absence of evidence to the contrary, that, by virtue of their training and experience, the Judges will rule fairly on the issues before them, relying solely and exclusively on the evidence adduced in the particular case.[8] The Appeals Chamber agrees with the ICTY Bureau that “a judge is not disqualified from hearing two or more criminal trials arising out of the same series of events, where he is exposed to evidence relating to these events in both cases”.[9] [See also para. 84 et seq. of the Appeal Judgement]

See also Hadžihasanović Appeal Judgement, para. 78.