## Facts

- Robert Alan Tapia was charged in Tulare County with first-degree murder with special circumstances for conduct occurring on February 12, 1989.
- Proposition 115 took effect on June 6, 1990, after voter approval, and made multiple changes to California criminal procedure and substantive law.
- Proposition 115 added Code of Civil Procedure § 223, shifting voir dire to judge-conducted examination “only in aid of the exercise of challenges for cause.”
- In Tapia’s pending prosecution for a pre–June 6, 1990 offense, the superior court ruled it would apply Proposition 115’s new procedural provisions, including the § 223 voir dire regime.
- Tapia sought writ relief to prevent application of Proposition 115 to his pre-effective-date offense; the Court of Appeal denied relief.
- The California Supreme Court granted review, issued an alternative writ, and stayed superior court proceedings pending decision.

## Issues

1. Whether, and to what extent, provisions of Proposition 115 may be applied in prosecutions for crimes committed before its June 6, 1990 effective date.
2. Whether Proposition 115’s trial-conduct provisions, including judge-conducted voir dire under Code of Civil Procedure § 223, may be applied to a pending prosecution for a pre-effective-date offense.
3. Whether substantive changes that disadvantage defendants may be applied to pre-effective-date conduct consistent with ex post facto limits.

## Decision

- The court held that certain Proposition 115 provisions governing the conduct of trials may be applied in prosecutions for crimes committed before June 6, 1990, so long as trial had not yet begun.
- The court held that certain provisions changing the law to the benefit of defendants may also be applied in such prosecutions.
- The court held that the remainder of Proposition 115’s provisions may not be applied to pre-effective-date crimes where they are substantive and disadvantage defendants.
- The court treated the new voir dire scheme in Code of Civil Procedure § 223 as a trial-conduct (procedural) rule that may be applied in Tapia’s pending case.
- The court granted partial writ relief consistent with these limits.
- The majority opinion was authored by Justice Panelli; Justices Mosk and Broussard dissented separately.

## Legal Principles

- Absent a contrary directive, statutes regulating the mode of trial and other trial-conduct procedures may be applied to pending prosecutions, including those involving offenses committed before the statute’s effective date, when trial has not commenced.
- Ex post facto constraints bar retroactive application of substantive changes that disadvantage defendants, including changes that increase punishment, alter offense definitions, or otherwise materially worsen the defendant’s position for pre-enactment conduct.
- Ameliorative changes benefiting defendants may be applied in pending cases involving pre-enactment conduct, absent a clear indication that such benefit is withheld.
- Voir dire allocation and method (including judge-conducted voir dire limited to challenges for cause) is a procedural matter concerning trial conduct rather than the elements of an offense or the punishment.

## Conclusion

The court permitted retroactive application of Proposition 115 only for trial-conduct procedures and provisions favorable to defendants in pending cases, while prohibiting retroactive application of substantive, defendant-adverse provisions to crimes committed before the initiative’s effective date.


Tapia v. Superior Court, 53 Cal. 3d 282, 807 P.2d 434 (Cal. 1991)