If an appeal marks a new era after trial, extraordinary writs occupy an even earlier and more urgent phase of appellate oversight. Writs of mandate and prohibition allow reviewing courts to intervene before final judgment, correcting significant legal errors that cannot be adequately remedied through the ordinary appellate process. Because writ relief interrupts ongoing proceedings and departs from the normal progression of litigation, it is considered an extraordinary remedy, granted sparingly and governed by strict procedural and substantive limits.

1. The Nature of Extraordinary Writs

California’s Constitution empowers the Supreme Court, courts of appeal, and superior courts to issue writs of mandate and prohibition.[i] A writ of mandate, also known as mandamus in other states, typically compels a lower court to perform a required legal duty or correct an abuse of discretion.[ii]  A writ of prohibition, by contrast, restrains a lower court from acting in excess of its jurisdiction.[iii]  While conceptually distinct—one compels action, the other restrains it—the two writs frequently overlap in practice. Courts focus less on labels and more on whether intervention is necessary to ensure lawful exercise of judicial authority.

2. When and Why Writ Relief Is Allowed

Writ review is not a substitute for appeal. It is appropriate only where the petitioner lacks a “plain, speedy, and adequate remedy in the ordinary course of law.”[iv]  This requirement is the central limiting principle of writ practice. Relief is most often considered where a trial court ruling threatens irreparable harm—such as compelled disclosure of privileged material, denial of a statutory right, or proceedings beyond the court’s jurisdiction—or where waiting for post judgment appeal would render review ineffective.[v] Appellate courts may also grant writ relief to resolve issues of widespread importance or novel legal questions requiring prompt guidance.[vi]  Even so, the vast majority of writ petitions are summarily denied, reflecting the discretionary and exceptional nature of the remedy.

3. Initiating the Proceeding: Petition and Record

Writ proceedings begin with the filing of a verified petition in the court of appeal. The petition must include a statement of the case, the relief sought, supporting points and authorities, and an adequate evidentiary record, typically presented through exhibits or an appendix.[vii]  The petitioner bears the burden of demonstrating both legal error and the inadequacy of ordinary appellate remedies. Because writ relief is often sought in time-sensitive contexts, proceedings move on an expedited basis, and strict compliance with procedural requirements is essential.

4. What to Expect from the Court

Most writ petitions conclude quickly and without written explanation. Summary denial does not constitute a decision on the merits and carries no precedential effect.[viii]  If the court determines that further consideration is warranted, it may request informal opposition, issue an alternative writ, or issue an order to show cause.[ix]  At that stage, the proceeding more closely resembles an appeal, with formal briefing and, in some cases, oral argument. A written appellate court opinion following such proceedings may be published and become binding precedent.

5. The Practical Realities of Writ Review

Because writs interrupt ongoing litigation, appellate courts approach them with caution, balancing the need for immediate correction against respect for trial court authority. Practitioners should expect close scrutiny of whether the issue is truly extraordinary. Routine evidentiary disputes or disagreements over discretionary rulings rarely justify relief. Narrowly framed issues, a clean procedural posture, and a well-organized record increase the likelihood of meaningful review.

6. Practice Tips for Writ Proceedings

Effective writ advocacy demands focus, urgency, and precision. Petitions should identify a clear legal error, demonstrate irreparable harm, and explain specifically why an appeal is not an adequate remedy. Overstated claims of emergency or attempts to relitigate routine matters undermine credibility. The supporting record must be complete and well organized, with requested relief carefully tailored to the legal issue presented. Above all, writ petitions should read as targeted requests for supervisory correction—not as substitute appeals.

Conclusion

If an appeal represents a new era after judgment, a writ petition seeks intervention before the current era even ends. It asks the appellate court to step in midstream, not to revisit a completed proceeding, but to ensure the rules governing the process are being followed in the first place. Understanding writ practice as a distinct and extraordinary phase—defined by urgency, discretion, and procedural rigor—helps practitioners recognize when this path is appropriate and how to navigate it effectively.

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Sources

[i] Cal. Const. art. VI, § 10.

[ii] Cal. Civ. Proc. Code § 1085.

[iii] Cal. Civ. Proc. Code § 1102.

[iv] Cal. Civ. Proc. Code § 1086.

[v] Omaha Indem. Co. v. Superior Ct., 209 Cal. App. 3d 1266, 1273 (1989).

[vi] Powers v. City of Richmond, 10 Cal. 4th 85, 113 (1995).

[vii] Cal. Rules of Court r. 8.486.

[viii] Kowis v. Howard, 3 Cal. 4th 888, 895 (1992).

[ix] Cal. Rules of Court r. 8.487.