Weinstein's Evidence P 606(04) (1978 & Supp. Dec. 1980); id. at 606-34 to -37. I need not decide that question, however, because defendants have not offered a juror's affidavit. Furthermore, counsel's statement is hearsay, not within any exception. Finally, even if admissible, the substance of the statement shows only that, in context, one juror contended that credibility issues should be resolved in favor of police. The statement does not demonstrate a juror believed police testimony solely because it was given by police, or that a juror lied during voir dire or otherwise came within the rule of Tobias, supra.
On cross-examination of a government informant, Robert Barron, counsel for defendant Donald Nickens stated at side bar that he wanted to inquire whether the informant's wife had been having an affair with Donald Nickens as well as some of the other defendants. Neither of the other defendants in their cross-examination had raised this issue. Donald Nicken's counsel was precluded from cross-examining on this area on the grounds that he could not (or would not) introduce corroborative evidence, and because the questions would have been inflammatory, confusing, and prejudicial. After careful review, I have decided that the wrong legal tests were applied; that under the proper tests, certain questions in this area were admissible; and that total preclusion of inquiry in this area of possible bias was plain error prejudicing all defendants.
Testimony is relevant if it would tend to change the probability of existence of bias or prejudice by the witness. See Fed.R.Evid. 401. Thus, a witness who believes his wife has been seduced by a defendant may be said to have a motive for testifying falsely against the defendant.
Contrary to the government's argument, the question is relevant. See generally, e.g., McCormick on Evidence § 40 (Cleary ed. 1972 & Supp. 1978); 3 Weinstein's Evidence P 607(03) (1978 & Supp. 1978); 2A Wigmore on Evidence §§ 943-949 (Chadbourn rev. ed. 1970 & Supp.1981); see also United States v. Moore, 174 U.S. App. D.C. 113, 529 F.2d 355, 357-58 (D.C.Cir.1976).
One reason for exclusion of questions was lack of collateral evidence. Although collateral evidence may be introduced to show bias, e.g., 3 Weinstein's Evidence P 607(3), at 607-17, collateral evidence is not prerequisite to cross-examination. The condition for inquiry into bias on cross-examination is whether counsel has a good-faith basis for the question. Here, counsel stated that his client had told him he had an affair with the witness's wife. This was an adequate good-faith basis for questioning.
Another reason for exclusion was the danger of undue prejudice or confusion. If one defendant's attorney had asked if the witness suspected his wife of having sexual relations with another defendant, and received a positive response, the other defendant would have been painted as an adulterer. This would have been substantially and unfairly prejudicial and confusing as to other defendants. Thus, Donald Nickens' counsel properly was prevented from inquiring about the witness's knowledge of affairs with other defendants. Danger to Donald Nickens himself, however, is another matter. That is his risk to take. See United States v. Moore, 529 F.2d at 357-58, after remand, 180 U.S. App. D.C. 227, 554 F.2d 1086, 1091 (D.C.Cir.1976). Because the questioning could have been limited to avoid exposing other defendants to unfair prejudice (by restricting each counsel to inquiring only about affairs with his own client), total exclusion was erroneous.
The error was "plain" because it interfered with a substantial right of the defendant. "The exposure of a witness' motivation in testifying is so significant that in a criminal case curtailment of this right may amount to a denial of confrontation or due process rights." 3 Weinstein's Evidence P 607(03), at 607-18. (footnotes omitted). Thus, I rule that the error was of constitutional proportions. Given that the testimony of Barron was central to the government's conspiracy case, preclusion of impeachment was not harmless. Each of the overt acts listed in the indictment in furtherance of the alleged conspiracy constituted separate substantive counts as to various defendants. Because the conspiracy evidence through Barron was inextricably interwoven with most of the evidence presented by other witnesses as to the substantive counts, it cannot be firmly said that the prejudice was limited to the conspiracy count. Finally, if evidence of bias had convinced the jurors that the witness had lied about one defendant, the jurors could have believed he would lie about the remaining defendants. Thus, it cannot be said that the error was harmless as to the remaining defendants, even though they may not have elected to take the risk in their own cross-examinations of Barron.
In conclusion, because exclusion of impeachment was error, affected substantial rights, and harmed all defendants, a new trial will be granted.
I have entered a separate appropriate order.