Recusal : of a judge : The Due Process Clause incorporated the common-law rule requiring recusal when a judge has “a direct, personal, substantial, pecuniary interest” in a case, Tumey v. Ohio, 273 U. S. 510, 523, but this Court has also identified additional instances which, as an objective matter, require recusal where “the probability of actual bias on the part of the judge or decisionmaker is too high to be constitutionally tolerable,”(…) that “every procedure which would offer a possible temptation to the average man as a judge to forget the burden of proof required to convict the defendant, or which might lead him not to hold the balance nice, clear and true between the State and the accused, denies the latter due process of law.”(…) The proper constitutional inquiry was not “whether in fact the justice was influenced,” id., at 825, but “whether sitting on that case . . . ‘ “would offer a possible temptation to the average . . . judge to . . . lead him not to hold the balance nice, clear and true,” ’ ” ibid. While the “degree or kind of interest . . . sufficient to disqualify a judge . . . ‘could not be defined with precision, ’ ” id., at 822, the test did have an objective component (…) the Court noted that the objective inquiry is not whether the judge is actually biased, but whether the average judge in his position is likely to be neutral or there is an unconstitutional “ ‘potential for bias (…) The proper inquiry centers on the contribution’s relative size in comparison to the total amount contributed to the campaign, the total amount spent in the election, and the apparent effect of the contribution on the outcome (…) And because the States may have codes of conduct with more rigorous recusal standards than due process requires, most recusal disputes will be resolved without resort to the Constitution, making the constitutional standard’s application rare (U.S.S.Ct., 08.06.09, Caperton v. A.T. Massey Coal Co., J. Kennedy).