In the 1985 case Delaware v. Van Arsdall, the U.S. Supreme Court ruled that a defendant's Sixth Amendment right to confront witnesses against him was violated when he was prohibited from cross-examining a prosecution witness about potential bias or motivation for testifying. The court held that such an error could be considered harmless and not require automatic reversal of conviction if, upon review, it is determined beyond reasonable doubt that the error did not contribute to the verdict obtained. This ruling established what is known as "harmless-error analysis" in Confrontation Clause cases - meaning courts must consider whether violation of confrontation rights had substantial influence on jury’s verdict before deciding on necessity of retrial.

In the dissenting opinion for Delaware v. Van Arsdall, Justice John Paul Stevens argued that the majority's decision to allow a retrial was incorrect and inconsistent with previous rulings on similar issues. He contended that the trial judge's error in restricting cross-examination of a prosecution witness did not automatically require reversal of conviction but should be evaluated based on whether it had substantial influence on jury verdicts. In this case, he believed there was no such influence as other evidence against defendant was strong enough to support his guilt beyond reasonable doubt even without considering testimony from said witness. Furthermore, he criticized the majority for creating confusion by introducing an unnecessary new rule instead of applying existing precedents correctly.