When an exception to the character evidence prohibition makes evidence of a criminal defedant's character admissible, the testimony of a witness on direct examination about the defendant's character must take the form of reputation or opinion and it cannot consist of specific instances of the defendant's conduct.

United States v. Nixon, 418 U.S. 683, pin? (1974) (claim of executive privilege rejected; Confrontation Clause and Compulsory Process Clause cited).A nonconstitutional privilege sometimes must yield to a criminal defendant's Sixth Amendment right to confront and cross-examine an adverse witness in a criminal trial. A nonconstitutional privilege privilege may have to yield to a criminal defendant's Confrontation Right when the privilege shields evidence or facts (particularly evidence or facts showing bias) that have significant probative value on the credibility of an adverse witness in a criminal trial who testifies about material facts in issue.

Cf. United States v. Naiden, 424 F.3d 718, 722-723 (11th Cir. 2005) (upholding trial court's exclusion of defendant's statement [that he did not believe his online acquaintance to be fourteen years old] as a state of mind....To fall within the hearsay exception created by Federal Rule of Evidence 803(3) or a comparable State rule for person's present internal states, a statement by the declarant (the maker of the statement) must be contemporaneous with the mental state or event sought to be proven.

Fed. R. Evid. 803(19) ("Reputation among members of a person's family by blood, adoption, or marriage, or among a person's associates, or in the community, concerning a person's birth, adoption, marriage, divorce, death, legitimacy, relationship by blood, adoption, or marriage, ancestry, or other similar fact of personal or family history.").There is a hearsay exception for reputation among members of a person's family by blood, adoption, or marriage, or among a person's associates, or in the community, concerning a person's birth, adoption, marriage, divorce, death, legitimacy, relationship by blood, adoption, or marriage, ancestry, or other similar fact of personal or family history.