More than a dozen state lawmakers and 1.2 million online petition-signers are calling for the state agency that investigates judicial misconduct to take disciplinary action against the judge in the Stanford sexual-assault case that sparked national outrage.

But a legal ethics expert cast doubt Friday on the contention that Judge Aaron Persky had violated rules of judicial conduct in sentencing a former Stanford athlete to six months in jail for sexual assault. And an organizer of a campaign to recall Persky said the last word should belong to the voters of Santa Clara County.

If the campaign qualifies the recall for the ballot, “voters will have an opportunity to decide whether they agree with his judicial philosophy,” Michele Dauber, a Stanford law professor and chairwoman of the recall committee, said at a rally outside the San Francisco headquarters of the state Commission on Judicial Performance.

About 50 rally-goers held up signs with messages like “Fire Judge Persky — Protect Survivors, Not Rapists” before organizers delivered petitions to the commission with what they said were 1.2 million signatures gathered online seeking the judge’s removal.

Separately, 16 state lawmakers weighed in Friday with a letter asking the commission to investigate the judge, whose sentencing of the former Stanford student, Brock Allen Turner, added fuel to an increasing national debate over what many are describing as an epidemic of sexual assaults on college campuses.

Turner was convicted of three felonies for sexually assaulting an unconscious woman outside a fraternity party on campus last year. The maximum sentence under state law was 14 years in prison, and prosecutors asked for six years.

But at the sentencing hearing June 2, Persky said a long prison sentence would have a “severe impact” on the 20-year-old, who had no previous criminal record and who would “not be a danger to anyone” after release. With good behavior behind bars, Turner will be eligible for release from Santa Clara County Jail after three months.

Misconduct alleged

In their letter to Anthony Capozzi, chairman of the state commission, members of the Legislature’s Women’s Caucus and Bay Area lawmakers said Persky had committed misconduct with preferential treatment of Turner.

“A prison sentence should have a severe impact upon a rapist,” they wrote.

The sentence, the lawmakers said, is “perceived by the public to be based on the fact that Turner is an upper middle class, white student-athlete who was privileged enough to earn both admission and an athletic scholarship to a highly selective university, just as Judge Persky did himself.”

Turner was a high school champion swimmer from Ohio. Persky, 54, graduated from Stanford. He was captain of the lacrosse team there for a year, according to a 2002 article in the Stanford Daily.

Before then-Gov. Gray Davis named him to the Superior Court bench in 2003, Persky was a sex-crimes prosecutor.

The lawmakers’ letter said the commission, which can reprimand or remove judges for conduct that violates judicial ethics, could find that Persky engaged in misconduct if it concludes he acted in a way that adversely affected the public’s perception of the judiciary.

“Judge Persky’s bias, whether intentional or inadvertent, affects the esteem of the judiciary in the eyes of the public, which undermines the public confidence in the integrity and the independence of the judiciary system,” the lawmakers wrote.

Judge’s ‘likely bias’

The online petition also referred to Persky’s “likely bias as a fellow former Stanford student-athlete,” and said his statements about the possible impact of a prison sentence on Turner represented “rape culture at its worst.”

But Diane Karpman, a Los Angeles attorney who has written extensively on legal ethics, said Friday that handing down an unpopular sentence does not amount to judicial misconduct, even if it reduces public esteem for the judiciary.

“This is all after the fact,” Karpman said. Noting that opposing parties in California courts have the one-time power to remove the judge at the start of the case, she said it was up to the prosecutor to look into Persky’s background at the outset and decide if he was biased.

“I’m equally dismayed (at Turner’s sentence), but I don’t think it was an issue of bias,” she said. Since the court’s probation office had recommended a sentence of six to 12 months in jail, Karpman said, legally “the judge was not standing on thin ice.”

The Santa Clara County Bar Association also spoke up Friday, saying the removal of a judge for a sentence in a single case would threaten judicial independence.

County Bar weighs in

The association said it had seen no credible evidence that Persky “violated the law or his ethical obligations or acted in bad faith” in sentencing Turner, and it was aware of no other allegations of impropriety against the judge in his 13 years on the bench.

Persky’s office has declined to comment on the uproar surrounding Turner’s sentencing.

Dauber, the Stanford law professor, said she was confident of collecting the 58,634 signatures needed to qualify a recall campaign against the judge for the ballot. She wasn’t sure when such an election could be held, but it could be in November 2017, when the county already has a special election scheduled.

Persky‘s current six-year term expires in January, but he did not appear on Tuesday’s primary ballot because no one ran against him. He will be automatically re-elected in November unless opponents submit 600 signatures to qualify a write-in candidate.

Other recall attempts

Other attempts to recall California judges for controversial rulings have fallen short, including one aimed this year at Marc Kelly, an Orange County Superior Court judge, for sentencing a convicted child molester to 10 years in prison instead of the 25 years that prosecutors said was the minimum allowed by law.

The legislators seeking an investigation of Persky have also sent another letter asking Santa Clara County District Attorney Jeff Rosen to seek a writ to have Persky’s “inappropriate and unlawful sentence” reviewed by another judge. A district attorney can seek an appellate review of a sentence, and if there is clear abuse of discretion by a trial judge, that sentence can be changed, the lawmakers wrote.

“Failure to use your authority as district attorney to seek appellate review sends the clear message to the public at large, including past and future victims of sexual assault, that you — a symbolic representative of our legal system — will not vigorously defend the rights of rape victims to the fullest extent of the law. We would find the failure to do so to be unconscionable,” the lawmakers said.

Assistant District Attorney James Gibbons-Shapiro said in a statement that prosecutors can only appeal a sentence that is unlawful.

“In this instance we believe that Judge Persky applied the right laws and reviewed the right circumstances and factors that he was required to review,” Shapiro said. “We believe that he made the wrong decision, that he should not have granted probation, that he should have sentenced Turner to prison. We asked that the judge impose a six-year prison sentence. We don’t believe that we have a basis to appeal or seek a writ in this case, though, because his decision was authorized by law and was made by applying the correct standards.”

Vow to fight on

Assemblywoman Susan Talamantes Eggman, D-Stockton, said in a statement that lawmakers will continue to fight to ensure justice is served.

“This confirms what women already knew: That rape culture blames us for being vulnerable when crimes are committed against us, but treats the same factors — drinking, in particular — as reasons to be exceedingly lenient with rapists,” Eggman said. “We will fight this with everything we have.”

Melody Gutierrez and Bob Egelko are San Francisco Chronicle staff writers. Email: mgutierrez@sfchronicle.com; begelko@sfchronicle.com Twitter: MelodyGutierrez; @egelko