Turbin v. Superior Court
In Turbin v. Superior Court, 165 Ariz. 195, 797 P.2d 734 (Ct. App. 1990), the Arizona Court of Appeals rejected the argument that, under the state's version of the Model Rules of Professional Conduct, a prosecutor's office could not be disqualified absent a showing of actual prejudice against a defendant.
The court found an appearance of impropriety standard to be the better test for two reasons. First, in many cases actual prejudice may exist but be extremely difficult to prove. Second, requiring a showing of actual prejudice ignores the principle that criminal prosecutions must appear fair.