dissenting:
I must dissent. The principal opinion unfairly ignores the Constitutional and codal rights of a military accused to present a defense at his court-martial. See United States v. Brown, 41 MJ 1 (CMA 1994). See generally Delaware v. Van Arsdall, 475 U.S. 673, 678-80, 106 S.Ct. 1431, 1434-36, 89 L.Ed.2d 674 (1986). Furthermore, it implicitly denigrates the members of courts-martial panels and their ability to consider and resolve questions of fact involving scientific evidence. See generally United States v. Hunt, 33 MJ 345 (CMA 1991); United States v. Murphy, 23 MJ 310 (CMA 1987). Finally, inexplicably, it undermines the integrity and evenhandedness of the Department of Defense Urinalysis Program and misconstrues the previous holding of this Court in United States v. Arguello, 29 MJ 198 (CMA 1989). See United States v. Sutton, 31 MJ 11, 18-19 (CMA 1990); United States v. Joyner, 29 MJ 209 (CMA 1989).1 All this the principal opinion does under the rubric of a judge’s discretion in excluding confusing or misleading evi*18dence under Mil.R.Evid. 403, Manual for Courts-Martial, United States, 1984.
I initially note that appellant was charged in two separate specifications with using marijuana, i.e., on July 27 and September 1, 1990. The Government proffered two witnesses to appellant’s use on the first occasion (Sergeant Robertson and Special Agent Johnson) and one witness to appellant’s use on the second occasion (Sergeant Robertson). The defense attempted to oppose this prosecution evidence by attacking the credibility and ability to observe of the government witnesses, by showing appellant’s good character, and by introducing evidence of a “negative” urinalysis test performed by the Government on September 4,1990. The military judge refused to admit the evidence of the negative urinalysis on the basis of Mil. R.Evid. 403, which states:
Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the members, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.
(Emphasis added).
The first question to be considered in this case is whether the defense has a Constitu-' tional and codal right to introduce the “negative” results of his urinalysis. This test was administered by the Government, without the accused’s consent, and was determined to be “negative” by the Government’s own standards. Moreover, the prosecution as a matter of routine uses the “positive” test results of urinalyses to establish the guilt of military accused at courts-martial. See Art. 46, Uniform Code of Military Justice, 10 USC § 846. In accord with our past precedent, I conclude that such evidence coupled with appropriate expert testimony is favorable to the defense on the question of nonuse2 and that appellant had a Constitutional and codal right to introduce such evidence of his innocence at his court-martial. United States v. Mack, 33 MJ 251 (CMA 1991); United States v. Joyner and United States v. Arguello, both supra. See generally Michigan v. Lucas, 500 U.S. 145, 111 S.Ct. 1743, 114 L.Ed.2d 205 (1991); Taylor v. Illinois, 484 U.S. 400, 407-10, 108 S.Ct. 646, 652-54, 98 L.Ed.2d 798 (1988). Consistent with our opinion in Arguello, once the defense had introduced this evidence, the Government could come in and explain the results to the factfinders using appropriate expert testimony. This procedure is fair to both parties.
The second question to be decided is whether the military judge may deny the defense its right to present this evidence because it might mislead the members. See Mil.R.Evid. 403. The existence of conflicting scientific evidence on the meaning and importance of urinalysis tests is well known. See United States v. Ford, 23 MJ 331 (CMA 1987); United States v. Harper, 22 MJ 157 (CMA 1986). Moreover, this Court has recognized that such scientific evidence is admissible as a matter of rebuttal if its particular rebuttal purpose is clearly delineated by the military judge. See United States v. Arguello, supra at 205. Finally, this Court has already held that it is Constitutional error to deny the defense the opportunity to challenge the Government’s scientific proof, its reliability, and its interpretation. See United States v. Van Horn, 26 MJ 434 (CMA 1988) . Accordingly, there is simply no authority for denying the defense evidence simply because the contrary scientific evidence might be admitted on its probative value. See generally Daubert v. Merrell Dow Pharmaceuticals, — U.S.-, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993).
*19The third question to be considered is whether the dispute engendered by admission of negative urinalysis evidence and properly delineated government rebuttal evidence was too confusing for the court-martial members to decide. See Mil.R.Evid. 403. This rule, like Fed.R.Evid. 403, does not extend to exclusion of evidence which is crucial to the defense. See also United States v. Brown, 41 MJ 1 (CMA 1994). In fact, it is black letter law that it is an abuse of discretion under Fed.R.Evid. 403 to exclude noncumulative crucial defense evidence. See J. Weinstein & M. Berger, Weinstein’s Evidence ¶ 403[06] at 403-88 to 403-89 (1994). See also Delaware v. Van Arsdall, 475 U.S. at 679, 106 S.Ct. at 1435. I conclude that this evidence was crucial to appellant’s defense.3 Finally, the members of courts-martial are routinely called upon to decide similar questions when the Government’s positive results in a urinalysis are challenged by defense scientific evidence. See United States v. Ford, supra.
The final question I must decide is whether admissibility of the urinalysis test results should be determined without regard for Department of Defense Directives. The test in this case was, after all, a urinalysis conducted pursuant to the Department of Defense Urinalysis Program. Its view of the reliability of tests results to show drug use in various circumstances is surely a matter to be considered under Daubert v. Merrell Dow Pharmaceuticals, supra. Moreover, it cannot seriously be contended that this program was promulgated by the Department of Defense without regard for the rights of individual servicemembers. See generally United States v. Caceres, 440 U.S. 741, 99 S.Ct. 1465, 59 L.Ed.2d 733 (1979).
In sum, the principal opinion permits, if not encourages, exclusion of all negative urinalysis evidence at courts-martial. It predicates such an exclusionary rule on the inability of court members to determine from expert testimony how probative such evidence is on the question of nonuse of drugs. Such a holding simply ignores the fact that for some 8 years this Court has held that positive urinalysis results accompanied by expert testimony are a sufficient basis for a rational court member to find beyond a reasonable doubt that an accused used drugs. See United States v. Harper, 22 MJ 157 (CMA 1986). Such a tilted playing field in my view not only violates the Constitution and the Uniform Code but also belatedly erodes the integrity of the military urinalysis program. Accordingly, I would reverse.
. Defense counsel made a pretrial motion to "prevent the Government, either in its case-in-chief or in rebuttal, from introducing evidence that would go under and try to explain a negative urinalysis____” The military judge, with the approval of the prosecution, however, granted this motion to the extent that the prosecution did not intend to affirmatively use the negative test results to show marijuana use by appellant. This ruling complies with the decision of this Court in United States v. Arguello, 29 MJ 198 (CMA 1989), which holds only that the Government cannot use scientific evidence coupled with a negative urinalysis to affirmatively show marijuana use at a court-martial.
. Trial counsel objected to the defense evidence of urinalysis on the basis of relevance (Mil. R.Evid. 401 and 402, Manual for Courts-Martial, United States, 1984), and undue confusion (Mil. R.Evid. 403). The prosecution called its expert Doctor Vasiliades who admitted the possible probative value of the negative tests. Trial counsel, in his argument, conceded this defense evidence had some probative value. The military judge also found "that this information proposed by the defense would be marginally relevant under [Mil. R.Evid.] 402, very marginally so____” The question of the relevance of a negative urinalysis to show nonuse is a question of expert testimony resolved in appellant’s favor at this court-martial. See generally United States v. Murphy, 23 MJ 310 (CMA 1987).
. See United States v. Brechtel, 997 F.2d 1108, 1114 (5th Cir.1993); United States v. Gaskell, 985 F.2d 1056, 1063 (11th Cir.1993); United States v. Stafford, 983 F.2d 25, 27-28 (5th Cir.1993); United States v. Foster, 982 F.2d 551, 555 (D.C.Cir.1993). See generally United States v. Spencer, 1 F.3d 742, 746, 748 (9th Cir.1992) (Reinhardt, J., dissenting).