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Cal. Rules of Prof. Conduct, rule 1.12 · Chapter 1. Lawyer-Client Relationship

Former Judge, Arbitrator, Mediator, or Other Third-Party Neutral

Verbatim from the official edition

Text — 2026 edition, as the State Bar of California publishes it (read October 22, 2026)

(a) Except as stated in paragraph (d), a lawyer shall not represent anyone in connection with a matter in which the lawyer participated personally and substantially as a judge or other adjudicative officer, judicial staff attorney or law clerk to such a person* or as an arbitrator, mediator, or other third-party neutral, unless all parties to the proceeding give informed written consent.*

(b) A lawyer shall not seek employment from any person* who is involved as a party or as lawyer for a party, or with a law firm* for a party, in a matter in which the lawyer is participating personally and substantially as a judge or other adjudicative officer or as an arbitrator, mediator, or other third-party neutral. A lawyer serving as a judicial staff attorney or law clerk to a judge or other adjudicative officer may seek employment from a party, or with a lawyer or a law firm* for a party, in a matter in which the staff attorney or clerk is participating personally and substantially, but only with the approval of the court.

(c) If a lawyer is prohibited from representation by paragraph (a), other lawyers in a firm* with which that lawyer is associated may knowingly* undertake or continue representation in the matter only if:

(1) the prohibition does not arise from the lawyer’s service as a mediator or settlement judge;

(2) the prohibited lawyer is timely screened* from any participation in the matter and is apportioned no part of the fee therefrom; and

(3) written* notice is promptly given to the parties and any appropriate tribunal* to enable them to ascertain compliance with the provisions of this rule.

(d) An arbitrator selected as a partisan of a party in a multimember arbitration panel is not prohibited from subsequently representing that party.

Notes and commentary — not rule text

Comment

[1] Paragraphs (a) and (b) apply when a former judge or other adjudicative officer, or a judicial staff attorney or law clerk to such a person,* or an arbitrator, mediator, or other third-party neutral, has personally and substantially participated in the matter. Personal participation includes both direct participation and the supervision of a subordinate’s participation, as may occur in a chambers with several staff attorneys or law clerks. Substantial* participation requires that the lawyer’s involvement was of significance to the matter. Participation may be substantial* even though it was not determinative of the outcome of a particular case or matter. A finding of substantiality should be based not only on the effort devoted to the matter, but also on the importance of the effort. Personal and substantial* participation may occur when, for example, the lawyer participated through decision, recommendation, or the rendering of advice on a particular case or matter. However, a judge who was a member of a multi-member court, and thereafter left judicial office to practice law, is not prohibited from representing a client in a matter pending in the court, but in which the former judge did not participate, or acquire material confidential information. The fact that a former judge exercised administrative responsibility in a court also does not prevent the former judge from acting as a lawyer in a matter where the judge had previously exercised remote or incidental administrative responsibility that did not affect the merits, such as uncontested procedural duties typically performed by a presiding or supervising judge or justice. The term “adjudicative officer” includes such officials as judges pro tempore, referees, and special masters.

[2] Other law or codes of ethics governing third-party neutrals may impose more stringent standards of personal or imputed disqualification. (See rule 2.4.)

[3] Paragraph (c)(2) does not prohibit the screened* lawyer from receiving a salary or partnership share established by prior independent agreement, but that lawyer may not receive compensation directly related to the matter in which the lawyer is personally prohibited from participating.

Source of truth

Edition
2026 edition, as the State Bar of California publishes it (read October 22, 2026)
Official file
https://www.calbar.ca.gov/sites/default/files/portals/0/documents/rules/Rules-of-Professional-Conduct.pdf (PDF pages 34–35)
Text hash
sha256 2469f374381bc93b9d1fbf5277849cf612aa10e9839f71c3bc239d557d7ff7fc
Composed by
rpc/build 2026-10-22: the State Bar's 2026 PDF (pages 12-71) read by two readers, PyMuPDF glyph positions and pdfminer with the PDF's tagged structure, agreeing on 834 of 843 paragraphs character for character, the other nine (paragraph boundaries only) resolved against the rendered page; 205,485 printed glyphs accounted for; the State Bar's chapter pages a third reading

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Procedural information only. Not legal advice and not a substitute for the advice of an attorney. Confirm the current text with the official publisher before relying on it.