Warren E. Burger

“ The impeachment process here undoubtedly provided valuable aid to the jury in assessing petitioner's credibility, and the benefits of this process should not be lost, in our view, because of the speculative possibility that impermissible police conduct will be encouraged thereby. Assuming that the exclusionary rule has a deterrent effect on proscribed police conduct, sufficient deterrence flows when the evidence in question is made unavailable to the prosecution in its case in chief.
Every criminal defendant is privileged to testify in his own defense, or to refuse to do so. ”

“ It is quite another to say that the defendant can turn the illegal method by which evidence in the Government's possession was obtained to his own advantage, and provide himself with a shield against contradiction of his untruths. ”

“ At trial the prosecution made no effort in its case in chief to use the statements allegedly made by petitioner, conceding that they were inadmissible under Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966) . The transcript of the interrogation used in the impeachment, but not given to the jury, shows that no warning of a right to appointed counsel was given before questions were put to petitioner when he was taken into custody. Petitioner makes no claim that the statements made to the police were coerced or involuntary. ”