State v. Madison
In State v. Madison, 114 Ariz. 221, 560 P.2d 405 (1977), the trial judge declared a mistrial upon learning after trial that a twelve-person jury was required and trial had proceeded with only eight. Id. at 223, 560 P.2d at 407.
In affirming the grant of the mistrial, the Arizona Supreme Court stated at one point that "had the trial judge not declared a mistrial and had proceeded to sentence the defendant 'reversal on appeal (would have been) a certainty.'" Id. at 224, 560 P.2d at 408.
However, it is clear that the supreme court did not decide whether the lack of a twelve-person jury when required mandated automatic reversal.
In the next sentence, the court indicated that the trial court "prevented a possible reversal on appeal and corrected the error." Id.
The reference to a "possible reversal" is exactly the opposite of the automatic reversal required by structural error.
Additionally, in Madison, the court indicated that "even if the trial court was in error in granting a mistrial, we see no prejudice to the defendant." Id. at 225, 560 P.2d at 409.