The California Supreme Court ruled today that judges who believe a mandatory 25 years to life sentence under the state's "three-strikes-andyou're-out" law is too harsh may ignore the law and impose a lighter sentence.

The landmark ruling by the state's highest court effectively emasculated the tough "three-strikes" sentencing law that was enacted by the legislature in 1994 to get habitual felons off the streets. The seven justices said their decision applies to past cases, thereby allowing thousands of prisoners to seek resentencing.

The three-strikes law was overwhelmingly endorsed by California voters in a November 1994 state referendum that was fueled by public anger over the kidnapping and murder of 12-year-old Polly Klaas by a paroled ex-convict. Klaas's killer, Richard Allen Davis, was convicted of murder on Tuesday and could face a death sentence.

At least 24 states have some version of the three-strikes law, which was based on a concept popularized in the 1992 presidential campaign and which later became a symbol of the national determination to crack down on crime by locking up for long terms habitual criminals who are responsible for most serious offenses. More states have habitual offender laws with enhanced sentences for multiple felony convictions.

Today's state Supreme Court decision followed a series of widely publicized cases in which Superior Court judges here -- and in some cases juries -- rebeled over the prospect of a defendant receiving a life sentence for a nonviolent felony such as burglary or drug possession. Some judges have refused to comply with the law, and in some cases juries pleaded with judges to reduce third-felony charges to misdemeanors or disregard prior convictions in order to circumvent the mandatory three-strikes sentence.

California Secretary of State Bill Jones, author of the law, condemned the court's ruling and said he will sponsor a bill to reinstate the mandatory 25 years to life sentence on third felonies for those previously convicted of two violent or serious felonies.

The law on which the court ruled today defines certain violent or serious crimes as "strikes" and mandates at least twice the usual prison term for a second strike. Third-strike defendants sentenced to the mandatory 25 years to life are not eligible for parole consideration until they have served 80 percent of their minimum sentence, or 20 years.

However, the law does give prosecutors the power to ask that a judge disregard a previous strike "in the furtherance of justice" and impose a lesser sentence. But it does not say whether judges can take such action on their own, an omission that has resulted in several conflicting rulings by state appellate courts and resulted in today's decision.

In writing for the court, Justice Kathryn Mickle Werdegar said, "Although the legislature may withdraw the statutory power {of judges} to dismiss in furtherance of justice, we conclude it has not done so in the threestrikes law."

Today's ruling was based on the case of a San Diego man, Jesus Romero, 32, whose previous "strikes" were for a residential burglary and a second attempted residential burglary. After he pleaded guilty in 1994 to possessing .13 grams of cocaine, a Superior Court judge ruled that 25 years to life would be cruel and unusual punishment and sentenced Romero to six years. A state court of appeals, acting at the behest of the prosecution, overruled the reduced sentence, and Romero's lawyers appealed to the Supreme Court.

Jones, a former Republican assemblyman, called today's decision a "clear affront" to the 72 percent of voters who approved the 1994 nonbinding referendum supporting the three-strikes law.

He said the three-strikes law has dramatically reduced crime over the last two years, and resulted in a "massive exodus" of parolees from California because of their fear of the law's tough third-strike sentences. In addition, California's crime rate has declined by 13.4 percent, far more than the drop in the national crime rate.

For that reason, Jones said, he will push legislation reinstating the mandatory aspect of the law.

Legal experts here said a state constitutional amendment would be needed to legislatively nullify the Supreme Court's ruling because six of the justices also held that the three-strikes measure, by tying judges' hands, violates the constitutional separation of legislative and judicial powers. The law was adopted in 1994 by more than two-thirds of the Assembly, then controlled by Democrats, a large enough majority to put a constitutional amendment on the ballot. Republicans now control the Assembly and could likely muster even more votes.

Critics of the law say it has hopelessly clogged the state's criminal courts because many defendants faced with the prospect of a life sentence are now demanding jury trials instead of plea bargaining. They also maintain that it has resulted in racial disparities in sentencing, with blacks accounting for 43 percent of three-strikes prison terms even though they make up only 20 percent of all felony arrests. A recent study found that 83 percent of those sentenced under the law are nonviolent offenders, most of them sentenced for drug violations.

Although today's court ruling has no legal effect on other states, it could be persuasive because California is often a bellwether on legal issues.