In the case of United States v. Taylor (1987), the Supreme Court ruled on whether a defendant's Sixth Amendment right to confront witnesses against him was violated when he was not allowed to cross-examine a government informant about his expectation of receiving leniency in exchange for testimony. The court held that it was error for the trial judge to prohibit all inquiry into this area, as such information could be relevant to assessing witness credibility and bias. However, they also found that this error did not automatically require reversal of conviction; instead, an appellate court should apply harmless-error analysis and consider factors like the importance of witness' testimony in prosecution’s case and if evidence corroborates or contradicts testimonial evidence on material points. In this specific instance, although there had been an infringement upon Taylor's rights under Confrontation Clause by restricting cross-examination regarding potential bias from expected leniency, it constituted harmless error due to overwhelming independent corroboration supporting guilt.

In the dissenting opinion for United States v. Taylor, Justice Blackmun argued that the majority's decision to allow evidence obtained through a warrantless search of a probationer's home undermined Fourth Amendment protections against unreasonable searches and seizures. He contended that while probationers do have diminished expectations of privacy, this does not equate to an abandonment of all rights protected by the Fourth Amendment. Furthermore, he disagreed with the majority’s view that allowing such searches would aid in rehabilitating offenders and protecting public safety; instead suggesting it could lead to arbitrary invasions of privacy without any real oversight or control. In his view, requiring a warrant based on probable cause before conducting such searches was not an undue burden on law enforcement agencies but rather served as essential protection for individual liberties.