Robert Alan Tapia (defendant) was indicted for committing first-degree murder with special circumstances on February 12, 1989. On June 6, 1990, Proposition 115, known as the Crime Victims Justice Reform Act (the Act), took effect. At that point, Tapia’s case had not gone to trial. As part of the act, a new voir dire statute provided that the court, instead of the attorneys, was to conduct the questioning of potential jurors. Shortly after the Act’s enactment, the Superior Court (respondent) ruled that it would apply the new statute’s voir dire requirements to Tapia’s case. Tapia petitioned the court of appeal for a writ of mandate to vacate the superior court’s order. The court of appeal denied Tapia’s petition and the Supreme Court of California granted review.