In 2004, reformers put an initiative on the ballot, Proposition 66, that would have reduced the number of people going to prison for life by removing nonviolent property and drug offenses from the list of three-strikes crimes. Gov. Arnold Schwarzenegger attacked the ballot measure. He credited three strikes for a major drop in crime — to the frustration of most experts, who point out that California’s dip began in 1991, well before three strikes passed, and ended in 2000. “The great weight of empirical studies discounts the role of three strikes in reducing crime,” states a 2004 report signed by six criminal-law professors, including Franklin Zimring at U.C. Berkeley. Still, Prop 66 fell short, with 47 percent of the vote.

Now California is in the midst of fiscal calamity. Supreme Court Justice Anthony Kennedy, who had been a judge in California, recently bemoaned state sentencing and spending on prisons. In an address at Pepperdine University, he said that “the three-strikes law sponsor is the correctional officers’ union, and that is sick!” And yet Schwarzenegger has vowed not to touch the law. Meg Whitman and Jerry Brown, the leading Republican and Democratic contenders to succeed him in November, are just as unbending.

IF THERE’S A WAY to reform three strikes, it may follow Norman Williams’s route out of prison. Michael Romano, who is 38, got his client released without opposition from the L.A. district attorney by forging a working relationship with Cooley’s office. The 63-year-old Republican prosecutor seems an unlikely ally for a young defense lawyer. He joined the D.A.’s office straight out of law school. His office notched more death sentences last year than the state of Texas, and his lunchmates include Pete Wilson, the former governor who signed three strikes into law. Yet despite his conservative bona fides, Cooley shares the conviction that some number of third-strike offenders like Norman Williams don’t belong in prison for life.

After three strikes became law, Cooley watched one of his colleagues in the D.A.’s office prosecute Gregory Taylor, a homeless man who at dawn one morning in 1997 went to a church where he’d often gotten meals and pried open the door to its food pantry. The priest later testified on his behalf. Taylor’s first crime was a purse-snatching; his second was attempting to steal a wallet. He didn’t hurt anyone. Taylor was sentenced to life. “It was almost one-upmanship, almost a game — bye-bye for life,” Cooley says, remembering the attitude in the office.

Three years later, Cooley ran for D.A. on a platform of restrained three-strikes enforcement, calling the law “a necessary weapon, one that must be used with precision and not in a scatter-gun fashion.” In office, he turned his critique into policy. The L.A. district attorney’s office no longer seeks life sentences for offenders like Norman Williams or Gregory Taylor. The presumption is that prosecutors ask for a life sentence only if a third-strike crime is violent or serious. Petty thieves and most drug offenders are presumed to merit a double sentence, the penalty for a second strike, unless their previous record includes a hard-core crime like murder, armed robbery, sexual assault or possession of large quantities of drugs. During Cooley’s first year in office, three-strikes convictions in Los Angeles County triggering life sentences dropped 39 percent. No other prosecutor’s office in California has a written policy like Cooley’s, though a couple of D.A.’s informally exercise similar discretion.

It’s a mistake, though, to cast Cooley as a full-tilt reformer. He opposed Prop 66 for ignoring a defendant’s criminal history. Instead, in 2006, he offered up his own bill, which tracked his policy as D.A., taking minor drug crimes and petty theft off the list of three-strikes offenses unless one of the first two strikes involved a crime that Cooley considers hard-core. For staking out even this middle ground, Cooley became prosecutor non grata among his fellow D.A.’s. No district attorney, not even the most liberal, supported his bill, and it died in Senate committee.

Cooley could once again pay a price for his three-strikes record. This spring, he announced his candidacy for California attorney general. His Republican rivals have hammered him for his moderate stance. “He’s acting as an enabler for habitual offenders,” State Senator Tom Harman told me. “I think that’s wrong. I want to put them in prison.” The race has developed into a litmus test: for 15 years, no serious candidate for major statewide office has dared to criticize three strikes. If Cooley makes it through his party’s primary on June 8 — and especially if he goes on to win in November — the law will no longer seem untouchable. If he loses, three strikes will be all the more difficult to dislodge.