If improperly obtained evidence is inadmissible in chief, is it necessarily inadmissible in cross-examination?
In Kansas v Ventris  USSC No 07-1356, 29 April 2009, the Court held (7 – 2) that an improperly obtained statement, from a jailhouse informant where the breach was of the Sixth Amendment right to counsel, which the prosecution conceded was inadmissible in chief, could be used in cross-examination to impeach the accused's inconsistent testimony.
This was on the basis, as Scalia J delivering the opinion of the Court (joined by Roberts CJ, Kennedy, Souter, Thomas, Breyer and Alito JJ) put it, that
"Our precedents make clear that the game of excluding tainted evidence for impeachment purposes is not worth the candle. The interests safeguarded by such exclusion are "outweighed by the need to prevent perjury and to assure the integrity of the trial process." Stone v. Powell, 428 U. S. 465, 488 (1976). "It is one thing to say that the Government cannot make an affirmative use of evidence unlawfully obtained. It is quite another to say that the defendant can provide himself with a shield against contradiction of his untruths." Walder, supra, [Walder v. United States, 347 U. S. 62, 65 (1954)] at 65. Once the defendant testifies in a way that contradicts prior statements, denying the prosecution use of "the traditional truth-testing devices of the adversary process," Harris, supra,[Harris v. New York, 401 U. S. 222, 225–226 (1971)] at 225, is a high price to pay for vindication of the right to counsel at the prior stage."
So, that's the rule. Scalia J, perhaps a little inconsistently, disavowed any rule-making function for the Court in his final footnote:
"Respondent's amicus insists that jailhouse snitches are so inherently unreliable that this Court should craft a broader exclusionary rule for uncorroborated statements obtained by that means. Brief for National Association of Criminal Defense Lawyers 25–26. Our legal system, however, is built on the premise that it is the province of the jury to weigh the credibility of competing witnesses, and we have long purported to avoid "establish[ing] this Court as a rule-making organ for the promulgation of state rules of criminal procedure." Spencer v. Texas, 385 U. S. 554, 564 (1967). It would be especially inappropriate to fabricate such a rule in this case, where it appears the jury took to heart the trial judge's cautionary instruction on the unreliability of rewarded informant testimony by acquitting Ventris of felony murder.[ He was convicted of aggravated burglary and aggravated robbery.]"
Stevens J (joined by Ginsburg J) dissented. He repeated his reasons for dissent in Michigan v Harvey, 494 U.S. 344 (1990).
On the topic of whether judges should adhere to earlier dissents, see blogs for 19 January 2007 and 16 January 2009.
He reasoned that the state's use of the improperly obtained evidence compounded the violation and promoted "shabby" police tactics.
This case is a reminder that an application to have evidence admitted may be renewed. The interests in using improperly obtained evidence in chief might not be the same as the interests in using it in cross-examination.
In New Zealand, our Evidence Act 2006 is silent on this point, but it does allow the use of voir dire evidence in cross-examination if the witness gives evidence that is inconsistent with evidence he gave at voir dire: s 15. Note s 90(1) and (2) which prohibit the use of inadmissible documents in questioning witnesses. At common law, use of an inadmissible statement in cross-examination was not permitted: Wong Kam-Ming v The Queen  AC 247. In R v Ryland 17/4/02, CA389/01 the Court referred to such a confession being "inherently inadmissible", contrasting it to evidence which had earlier in the trial lacked an evidential foundation for its relevance but which subsequently became relevant.