joined by
Judge . SCHREIER,(concurring in part and dissenting in part):
Speaking for the majority in United States v. Gipson, Judge Cox summarized his view on the reliability of polygraph evidence:
In our assessment, the state of the polygraph technique is such that, depending on the competence of the examiner, the suitability of the examinee, the nature of the particular testing process employed, and such other factors as may arise, the results of a particular examination may be as good as or better than a good deal of expert and lay evidence that is routinely and uncritically received in criminal trials. Further, it is not clear that such evidence invariably will be so collateral, confusing, time-consuming, prejudicial, etc., as to require exclusion.
United States v. Gipson, 24 M.J. 246, 253 (C.M.A.1987).
If Judge Cox is right, and we think he is, this appellant was denied his constitutional right to lay the foundation for relevant, material, and favorable exculpatory evidence vital for his defense. See, e.g., Chambers v. Mississippi 410 U.S. 284, 93 S.Ct. 1038, 35 L.Ed.2d 297 (1973) (accused’s right to present evidence); Gipson, 24 M.J. at 254 app. (listing of articles and treatises on reliability of polygraphs); McMorris v. Israel 643 F.2d 458, 461-462 (7th Cir.1981) (“[W]e note that even the most ardent detractors from the validity of polygraph evidence concede a degree of reliability of 70% or higher for prop*695erly administered examinations.”), cert. denied, 455 U.S. 967, 102 S.Ct. 1479, 71 L. Ed.2d 684 (1982). See also Daubert v. Merrell Dow Pharmaceuticals, Inc., — U.S. -, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993) (standard for admitting expert testimony under Fed.R.Evid. 702); United States v. Garcia, 40 M.J. 533 (A.F.C.M.R.1994) (standard for admitting expert testimony under Mil.R.Evid. 702); United States v. Combs, 35 M.J. 820 (A.F.C.M.R.1992) (same), aff'd, 39 M.J. 288 (C.M.A.1994).
Litigated urinalysis cases often present the classic man versus machine contest. There are no eye witnesses to the urinalysis based drug charge, nor any witnesses who testify the accused was somehow impaired, nor any other corroborating evidence of drug use. Likewise, there is no evidence to show where or how the accused allegedly used the drug, or a precise time of use. Instead, machines — operated by humans — produce results — interpreted by humans — which the prosecution uses to procure a conviction. In this regard, the prosecutor calls an expert witness to explain that the machine results show the accused’s urine specimen contained a metabolite of a chemical compound which is found in the drug charged. Consequently, the prosecution’s case rests entirely on scientific evidence offered under Military Rule of Evidence 702.
Do urinalysis machines, or their operators, make “mistakes” which go undetected through normal quality control? We need only look at Pentium computer chips that can’t divide, nuclear reactors that go haywire, and space shuttles that don’t launch to answer that question.
So what if you are wrongfully accused of drug use based on an erroneous urinalysis result? You have no eyewitnesses to shake on cross-examination, or to help you. You have no alibi witnesses unless you are in direct observation of someone for 24 hours a day, 7 days a week, since it only takes a moment alone to snort cocaine or consume most other drugs. Because of the nebulous nature of the prosecution’s evidence, you basically have only your word. But, why should a judge or jury believe you, as opposed to the prosecution’s “scientific” evidence, if you chose to testify? Credibility!
In a urinalysis case, the accused’s credibility becomes the whole ball game if the accused denies use since urinalysis machines can’t be cross-examined. If the court convicts, it chooses not to believe the accused, the only real witness to the offense. Thus, evidence reflecting favorably on the credibility of the accused’s denial is relevant, material, and vital to the defense in a urinalysis case where the accused takes the stand, which brings us to polygraphs.
Polygraphs are also machines — operated by humans — which produce results — interpreted by humans. Polygraph evidence reflects on the credibility of an accused’s denial of having used the drug charged. Gipson, 24 M.J. at 253; McMorris, 643 F.2d at 461-2. Is it admissible on an accused’s behalf — we think so in spite of the absolute prohibition in Military Rule of Evidence 707. See United States v. Williams, 39 M.J. 555 (A.C.M.R. 1994).
We agree the President may promulgate rules of evidence for trials by court-martial. However, the President may not promulgate a rule which infringes on an accused’s constitutional right to present relevant, material, and favorable evidence. See, e.g., Ellis v. Jacob, 26 M.J. 90 (C.M.A.1988) (striking down President’s rule in R.C.M. 916(k)(2) precluding accused from presenting evidence of partial mental responsibility to negate state of mind element of an offense); United States v. Hollimon, 16 M.J. 164 (C.M.A.1983) (recognizing constitutional limit on President’s bar in Mil.R.Evid. 412(a) on admission of reputation or opinion evidence of noneonsensual sexual offense victim’s past sexual behavior).
Consequently, we recognize a constitutional escape clause to Military Rule of Evidence 707, similar to that found expressly in Rule 412(b) which excludes evidence of a nonconsensual sexual offense victim’s past sexual behavior. Polygraph evidence is not admissible unless it is “constitutionally required to be admitted,” that is, unless it is relevant, material, and favorable to the defense. Cf. United States v. Williams, 37 M.J. 352 (C.M.A.1993) (constitutionally required evi*696dence under Mil.R.Evid. 412). In this regard, military judges should “view liberally the question of whether the expert’s testimony may assist the trier of fact.” Combs, 35 M.J. at 826. And, “[i]f anything, in marginal cases, due process might make the road a tad wider on the defense’s side than on the Government’s.” Gipson, 24 M.J. at 252.
Here, the military judge did not afford appellant the opportunity to show his polygraph evidence met the constitutionally required criteria for admission. Consequently, we would return the record of trial to The Judge Advocate General for remand to the convening authority for a hearing on the admissibility of the proffered polygraph evidence in accordance with the procedures outlined in United States v. Williams, 39 M.J. at 559.