Harris (defendant) was arrested for selling drugs to an undercover police officer. At trial, Harris testified. During cross examination, the prosecution attempted to impeach Harris’ earlier testimony by asking questions about unwarned statements Harris made following arrest. The jury was instructed that the statements could only be used to assess Harris’ credibility. The statements were not used during the prosecution’s case in chief. Both attorneys discussed the statements during closing arguments. Harris was found guilty. In a per curiam opinion, the Court of Appeals of New York affirmed the conviction. The United States Supreme Court granted certiorari.