In what circumstances will the US Supreme Court uphold section 1108 of the Civil Code of Civil Procedure, which bars a defendant from using propensity evidence?

But as previously explained, even if the rule were deemed fundamental from a historical perspective, we would nonetheless uphold section 1108 if it did not unduly "offend" those fundamental due process principles. (See, e.g., Medina v. California, supra, 505 U.S. at pp. 444-446, 112 S.Ct. 2572; Patterson v. New York, supra, 432 U.S. at p. 202, 97 S.Ct. 2319.) As will appear, in light of the substantial protections afforded to defendants in all cases to which section 1108 applies, we see no undue unfairness in its limited exception to the historical rule against propensity evidence.