On May 28, 2026, the California Supreme Court issued a significant decision in J.O. v. Superior Court of San Joaquin County, holding that courts may, in certain circumstances, look behind peremptory judicial disqualification motions under Code of Civil Procedure section 170.6 when those motions appear to be part of a coordinated “blanket” effort to remove a judge. The decision marks a departure from nearly five decades of precedent and introduces a new procedural framework that will affect litigants who regularly appear in California courts, particularly institutional parties and their opponents.

Section 170.6 and Prior Law.  Section 170.6 permits a party or attorney to disqualify a judge based on an asserted belief that the judge is prejudiced. When the attorney complies with the statute’s complex timing requirements and properly invokes the statute, the disqualification is automatic and a new judge must be assigned without any inquiry into the truth of the asserted prejudice. Although courts have long recognized that this right may be abused—for example, through “judge-shopping” or retaliatory challenges—prior precedent, most notably Solberg v. Superior Court (1977), held that even systemic or “blanket” uses of section 170.6 did not violate separation-of-powers principles and ensured that a party would be able to disqualify a biased judge even if that bias would be difficult to prove.

But since 1977, caseloads have ballooned, budget constraints have limited court operations, and superior courts have become heavily reliant on specialized courtrooms that depend on stable judicial assignments. Systematic peremptory strikes have the potential to compromise judicial independence and disrupt case management and resource allocation.

The California Supreme Court Limits Systematic Peremptory Strikes. In J.O., petitioner’s opposing counsel, the San Joaquin County Counsel’s Office, commenced a targeted campaign of section 170.6 disqualifications against a judge who had admonished a member of the County Counsel’s Office. The County Counsel filed over 300 challenges in less than four months, illustrating the degree to which section 170.6 can be used to affect the administration of justice in superior court.

The California Supreme Court held that, while section 170.6 remains facially constitutional, its blanket abuse can, in certain circumstances, materially impair the judiciary’s core function of administering justice and therefore violate separation-of-powers principles. As a result, the Court overruled Solberg to the extent it barred as-applied challenges to such practices. Court established that:

• If an opposing party makes an initial showing that section 170.6 motions are being used as part of a blanket policy of bad-faith challenges (that is, not based on the court’s impermissible bias against the counsel) against a particular judge, courts may inquire into the legitimacy of those challenges.
• The burden then shifts to the movant to articulate a good-faith, case-specific basis for the challenge. Thereafter, the court determines whether the pattern reflects improper blanket disqualification.

The Court emphasized that this inquiry does not restrict a party’s ability to make good-faith disqualification motions in individual cases.

Practical Impacts.  The decision has several practical implications, particularly for litigants engaged in significant or repeat litigation in California courts.

• Institutional litigants—including government entities, large corporate defendants that appear regularly in the same superior court, and frequent plaintiffs—will face heightened scrutiny if they regularly file section 170.6 motions against the same judge or category of assignments.
• The new burden-shifting framework introduces litigation risk around disqualification motions. Opponents may challenge such motions, potentially resulting in hearings, delay, and adverse factual findings regarding litigation strategy.
• The decision reduces the predictability of using section 170.6 to manage judicial assignments—particularly in specialized dockets (e.g., complex civil, employment, or regulatory proceedings).

The California Supreme Court’s decision in J.O. significantly recalibrates the balance between litigants’ rights to disqualify judges and the judiciary’s authority to manage its docket. By allowing courts to police bad-faith “blanket” uses of section 170.6, the decision introduces a new constraint on an historically automatic procedural tool.