California Supreme Court Cracks Down on "Judge-Shopping by the Truckload"

What Happened

On May 28, 2026, the California Supreme Court issued a major ruling that changes the rules around one of the most powerful — and most abused — tools in California litigation: Code of Civil Procedure section 170.6, the "peremptory challenge" that lets any party kick a judge off their case, no questions asked, no reasons required.

The case is J.O. v. Superior Court, and the headline is simple: courts can now look behind a mass pattern of judge challenges and ask whether the party is acting in bad faith — something the Court had said for almost 50 years was off-limits.

The Backstory

Section 170.6 is famous (or infamous) among California lawyers. If you don't like the judge assigned to your case, you can file a one-page sworn statement saying the judge is "prejudiced" against you — and the judge is automatically removed. No proof required. No hearing. It just happens.

That power exists so litigants have somewhere to turn if they genuinely believe a judge is biased and can't prove it. But it has a dark side: nothing stops a party — especially a government office or law firm that appears in court constantly — from using it over and over against the same judge, in case after case, simply because they don't like how that judge rules.

That's exactly what allegedly happened here. In San Joaquin County, a judge named Erin Guy Castillo handled conservatorship cases (a type of court proceeding for people who can't care for themselves). After she admonished an attorney from the County Counsel's office for improper conduct, that office allegedly began filing a section 170.6 challenge against her in every single conservatorship case — an estimated 325 challenges in under four months. The pressure eventually forced the presiding judge to reassign her out of conservatorship work entirely and into misdemeanors, traffic tickets, and small claims.

One of the people caught in the middle — referred to as "J.O.," a person under a conservatorship — tried to fight back, arguing the County Counsel's mass campaign was unconstitutional. But the trial court cited a 1977 California Supreme Court case called Solberg and said: sorry, courts aren't allowed to even look into whether a "blanket" challenge campaign like this is being made in bad faith. The Court of Appeal agreed and shut the door too.

Why This Went to the Supreme Court

That old 1977 rule — that courts must stay blind to obvious patterns of abuse — put judges in an impossible spot. If an office decides to systematically remove a specific judge from every case of a certain type, that judge simply can't do the job the presiding judge assigned them to do, no matter how well-qualified or fair they are.

J.O. asked the Supreme Court to revisit that decades-old rule, arguing that today's courts — bigger caseloads, more specialized judges, tighter budgets — can't afford to let this kind of abuse go unchecked.

What the Supreme Court Decided

The Court agreed to reopen the question — and it changed the rule.

The old rule (1977–2026): Courts had to accept every section 170.6 challenge at face value, no matter how obviously it looked like part of a coordinated campaign against one judge.

The new rule: If a party can show a pattern suggesting a judge is being challenged over and over in bad faith — not because of a genuine belief in bias in a specific case, but to punish them, pressure them, or force them off a calendar — a court can now dig deeper and ask the challenging party to explain themselves.

The Court borrowed a process from a well-known jury selection case (Batson v. Kentucky) and built a three-step test:

1. Step 1 — Raise the flag. The person objecting to the challenge has to show a pattern: for example, the same office striking the same judge in nearly every case, or in every case of a certain type.

2. Step 2 — Explain yourself. If that pattern is shown, the burden shifts to whoever filed the challenges. They have to give a real, case-specific reason for believing the judge was actually biased against them — not just "we didn't like their rulings."

3. Step 3 — The judge decides. A different judge then decides whether the explanation is genuine or just a cover story. If it's bad faith, the challenge is denied and the original judge stays on the case.

Why the Court Changed Its Mind

The justices pointed to how much California's court system has changed since 1977:

• Way more cases are filed today than back then.

• Courts have far fewer resources and are chronically short on judges.

• The rise of specialized courts (family court, mental health court, drug court, and others) means yanking one trained judge off their calendar hurts the whole system, not just one case.

Given all that, the Court said a mass campaign against a single judge isn't just an inconvenience anymore — it can actually interfere with a court's constitutional job of fairly running its own business. That crosses into "separation of powers" territory: the Legislature can give people tools like section 170.6, but not tools so powerful they let outside parties override how courts assign their own judges.

Importantly, the Court made clear this rule isn't limited to prosecutors or government lawyers. Any party — a law firm, a company, an individual litigant — can be challenged if their pattern of judge-shopping crosses into bad faith.

What This Doesn't Change

The Court was careful to say this ruling is not a wholesale takedown of section 170.6:

• If you have a genuine, good-faith belief that a judge is biased against you in your specific case, you can still use section 170.6 exactly as before — no proof needed, no questions asked.

• Simply disliking a judge's past rulings, legal philosophy, or courtroom style still isn't a valid reason to disqualify them — that was already true, and it still is.

• One-off challenges, or challenges spread across different judges for different genuine reasons, are unaffected. This is squarely aimed at patterns of mass, repeated targeting of one judge.

Why This Matters

This ruling directly protects judicial independence. Without it, any office or firm with enough cases on file could effectively handpick their judges by wearing down anyone who rules against them — forcing that judge off the calendar entirely rather than risk being challenged in every future case. That undermines the whole point of having assigned, impartial judges in the first place.

It also matters for smaller counties, where there might only be two judges total — meaning a mass challenge campaign could functionally let a party pick which of the two judges hears all their cases.

The Bottom Line

Section 170.6 is still one of the fastest, easiest tools in California litigation — and it still doesn't require proof of actual bias. But it's no longer bulletproof against scrutiny. If a party's challenges start looking less like isolated good-faith disqualifications and more like a coordinated campaign to push one judge off the bench, courts can now ask hard questions — and if the answers don't hold up, the judge stays.

This post summarizes J.O. v. Superior Court, 19 Cal.5th 753 (Cal. May 28, 2026), for general informational purposes. It is not legal advice.