In the 1985 case Lee v. Illinois, the U.S Supreme Court ruled that a confession made by one defendant could not be used as evidence against another defendant unless it was corroborated by other evidence. The case involved two defendants, Tommy Lee and James Grayson, who were tried together for murder. During their trial, a statement given to police by Grayson implicating both himself and Lee in the crime was admitted into evidence even though Grayson did not testify at trial. This meant that Lee's attorney had no opportunity to cross-examine him about his statement. The court found this violated the Confrontation Clause of the Sixth Amendment which guarantees defendants in criminal cases the right "to be confronted with witnesses against them." As such, they concluded that an exception to this rule should only apply when there is substantial independent indicia of reliability.

In the dissenting opinion for Lee v. Illinois, Justice Brennan argued that the majority's decision to allow a co-defendant's confession as evidence against another defendant violated the Sixth Amendment right to confront witnesses. He stated that such confessions are inherently unreliable and should be treated with extreme caution due to their potential for coercion or fabrication. Furthermore, he pointed out that this ruling contradicts previous Supreme Court decisions which have consistently held that defendants have a constitutional right to cross-examine all witnesses against them. In his view, allowing an exception in this case undermines these protections and sets a dangerous precedent for future cases.