State v. Huerta
In State v. Huerta, 175 Ariz. 262, 266, 855 P.2d 776, 780 (1993) the Arizona Supreme Court characterized peremptory challenges as a substantial right that is "clearly impinged" when a trial court erroneously denies a for-cause challenge.
In Huerta, the majority's rejection of the harmless-error rule advocated by the two dissenting justices was premised on the following rationale:
Under the Hobson's choice presented by the dissent, the defendant who strikes the biased juror can never show prejudice, but the defendant who leaves the biased juror on the panel waives the issue.
It seems that under the dissent's view, a party can only show reversible prejudice if the judge erroneously denies one more challenge for cause than a party has peremptory challenges.
Such a holding would encourage parties to make increased efforts to demonstrate bias on the part of some of the other jurors . . . which would lead to an ongoing trial of the jurors instead of the merits of the case. We do not wish to adopt a rule that will encourage and place a premium on such gamesmanship and nonproductive judicial proceedings. 175 Ariz. at 266, 855 P.2d at 780.