(concurring).
In light of the customs that once prevailed, a woman’s chastity was viewed by many jurists as relevant to her credibility. On this premise, acts of extramarital intercourse were a proper subject of cross-examination for impeachment purposes. Moreover, promiscuity represented such a departure from accepted morality that evidence of voluntary intercourse on one occasion with one man was admissible to establish that a prosecutrix had probably consented to intercourse on an entirely different occasion with a different man.
In recognition of the sexual revolution in the western world, critics began to question whether a fornicator is any less credible than someone who has adhered to traditional sexual mores, or whether consent to intercourse with A implies any readiness to have sexual relations with B. Reinforced by feminist activity and heightened concerns for privacy, doubts as to the relevance of evidence of extramarital sexual relations by a witness or prosecutrix ripened into judicial decisions excluding such evidence, cf. United States v. Kasto, 584 F.2d 268 (8th Cir.1978), cert, denied, 440 U.S. 930,99 S.Ct. 1267, 59 L.Ed.2d 486 (1979), and into the rape shield provisions of federal, state, and military law.1
However, as the principal opinion makes clear, Mil.R.Evid. 412 is primarily a rule of relevance. Thus, just as evidence of an accused’s past misdeeds may be admitted when offered for a purpose other than to demonstrate that he is a bad person with a propensity for crime, see Mil.R.Evid. 404(b); cf. United States v. Haimson, 5 U.S.C.M.A. 208,17 C.M.R. 208 (1954), evidence of sexual misconduct by a witness or prosecutrix may be received when it has relevance apart from suggesting that a promiscuous person is not credible and is prone to engage indiscriminately in sexual intercourse. For example, evidence of a witness’ close sexual relationship with a third person who is hostile to an accused might tend to indicate that the witness also is hostile to the accused; and so this evidence should be admitted. Likewise, evidence that, shortly before an alleged rape, the prosecutrix had *30sexual intercourse with a third person would be admissible to explain how semen discovered by doctors in examining her soon after the event might have had a source other than the accused. Further, evidence of a victim’s reputation or prior conduct — if known to the accused — might negate the specific intent required in sex crimes that contain this element or might demonstrate the accused’s honest but mistaken belief that the alleged victim had consented.
As a rule of relevance, Mil.R.Evid. 412 must not be applied mechanically by military judges. Otherwise, a trespass will occur against the sixth-amendment rights of accused to confront prosecution witnesses, cf. Davis v. Alaska, 415 U.S. 308, 94 S.Ct. 1105, 39 L.Ed.2d 347 (1974), and to offer defense evidence, cf. Washington v. Texas, 388 U.S. 14, 87 S.Ct. 1920, 18 L.Ed.2d 1019 (1967); United States v. Nixon, 418 U.S. 683, 94 S.Ct. 3090, 41 L.Ed.2d 1039 (1974); Chambers v. Mississippi, 410 U.S. 284, 93 S.Ct. 1038, 35 L.Ed.2d 297 (1973).
In the case at bar, the defense argument for the relevance of the excluded evidence would have been strengthened if — as in United States v. Ferguson, 14 M.J. 840 (A.C.M.R.1982) — it had been coupled with an offer of psychiatric testimony linking more explicitly the infidelity of the prosecutrix’ husband to her claimed urge to extract revenge by sleeping with her fellow taxi cab drivers and passengers.2 However, for the reasons expressed in the principal opinion, I conclude that the evidence offered by appellant slipped across the threshold of admissibility.
Often the mistaken exclusion of defense evidence because of an overly rigid application of Rule 412 will require reversal. See, e.g., United States v. Dorsey, 16 M.J. 1 (C.M.A.1983). That outcome, however, is not inevitable; and since — for reasons also explained in the principal opinion — beyond any reasonable doubt appellant was not prejudiced by the error, I join in affirming the findings and sentence.
. For a discussion of the rape shield laws, see, e.g., Tanford and Bocchino, Rape Victim Shield Laws and the Sixth Amendment, 128 U.Pa.L. Rev. 544 (1980); Berger, Man’s Trial, Woman’s Tribulation: Rape Cases in the Courtroom, 77 Colum.L.Rev. 1 (1977). See also Annot., 1 A.L.R. 4th 283 (1980).
. A defense counsel must establish clearly at trial the basis for admissibility of evidence which the Government seeks to exclude under Mil.R.Evid. 412. Cf. United States v. Nez, 661 F.2d 1203 (10th Cir.1981); Logan v. Marshall, 680 F.2d 1121 (6th Cir.1982); United States v. Holy Bear, 624 F.2d 853 (8th Cir.1980). Only in this way is the relevance of such evidence made apparent. Cf. Mil.R.Evid. 401 and 402.