In my experience, there is a good deal of confusion about what is meant by the "one challenge per side" rule governing peremptory challenges to assigned trial judges under Code of Civil Procedure section 170.6.  In Pickett v. Superior Court (February 22, 2012), the Court of Appeal (Second Appellate District, Division Five) reduced at least some of that confusion, upholding the right of the plaintiff in a second, related action to exercise a peremptory challenge after the plaintiff in the earlier-filed action had already done so.

Pickett’s action that included a Private Attorney General Act (Lab. Code, § 2698 et seq.) (PAGA) claim.  It was deemed related to a prior-filed PAGA action brought by Eugina Bright, against the same defendant, 99¢ Only Stores, on similar allegations.  The two action sought somewhat different remdies.  Pickett’s action was reassigned to the all-purpose judge in the prior-filed action, but not consolidated with that first action.  Pickett timely filed a peremptory challenge to the trial judge pursuant to Code of Civil Procedure section 170.6.

The trial court struck the challenge as improper.  It determined that Pickett’s action was identical to and a continuation of the action brought by Bright, who had already used her one peremptory challenge in the matter after remand following a successful appeal.  The Court of Appeal concluded that under section 170.6 and the authorities applying it, Pickett’s action is not a continuation of Bright’s action, nor is Pickett on the same “side” as Bright in one action, and therefore Pickett’s peremptory challenge should have been accepted.

An interesting extra detail is that in the Notice of Related Cases, Pickett described her claims as "identical" to Bright's.  Despite that characterization, one that the defendant sought to turn to its advantage, the Court of Appeal determined that the right to exercise a peremptory challenge should be determined by the nature of the cases and identity of the parties, not the characterization by a party in a Notice of Related Cases.