William J. Brennan, Jr.

“ First, defendants sometimes need to call "reluctant" or "hostile" witnesses to provide reliable and probative exculpatory testimony, and such witnesses likely will not share the defendants' concern for avoiding statements that invite impeachment through contradictory evidence. Moreover, defendants often cannot trust even "friendly" witnesses to testify without subjecting themselves to impeachment, simply due to insufficient care or attentiveness. ”

“ Defendants might reasonably fear that one or more of their witnesses, in a position to offer truthful and favorable testimony, would also make some statement in sufficient tension with the tainted evidence to allow the prosecutor to introduce that evidence for impeachment. ”

“ Narrowing the exclusionary rule in this manner, therefore, would significantly undermine the rule's ability "to compel respect for the constitutional guaranty in the only effectively available way by removing the incentive to disregard it." ”

“ Given the inherent subjectivity of this proposed test, a defendant could hardly be confident that all witness statements that are actually inadvertent or surprising to the defendant will be found to be such by the trial court so as not to open the door to impeachment. This proposed limitation thus would not meaningfully blunt the chill imposed on defendants' presentation of witnesses.↑ Brief for United States as Amicus Curiae 18-22.↑ Indeed, the detectives who unlawfully detained James and elicited his incriminating statements already knew that there were several eyewitnesses to the shooting. ”