In the case of Smith v. Illinois in 1984, the United States Supreme Court ruled that a defendant's Sixth Amendment right to confront witnesses against him was violated when he was not permitted to cross-examine a state witness about his alias and pending charges. The court held that such information could have been used by the defense to suggest bias or interest on part of the witness, which is crucial for assessing credibility. This decision reaffirmed that defendants are entitled under the Confrontation Clause of the Sixth Amendment to probe into potential sources of bias and prejudice from prosecution witnesses during cross-examination.

In the dissenting opinion for Smith v. Illinois, Justice Stevens argued that the majority's decision to reverse and remand was unnecessary because there was no ambiguity in the defendant's request for counsel during his interrogation. He believed that any reasonable police officer would have understood it as a clear invocation of his right to counsel under Miranda v. Arizona (1966). According to him, by ignoring this fact, the Court effectively allowed law enforcement officers to continue questioning suspects until they obtained a waiver of their rights or an incriminating statement - even after those suspects had clearly invoked their rights under Miranda. This approach undermined both the letter and spirit of Miranda and its progeny which were designed specifically to protect individuals from coercive interrogations without legal representation.