Prior to United States v. Hinkson, under the prevailing analysis used to determine whether the trial court had engaged in an “abuse of discretion,” there was arguably “no effective limit” on an appellate court’s power to substitute its own judgment for that of the district court. Rather, it was left to the appellate panel to decide whether it had a “definite and firm conviction that [a] mistake [had] been committed,” or whether a trial court’s factual finding was even “permissible.” But in Hinkson, an en banc panel of the Ninth Circuit took the opportunity to elaborate on the abuse-of-discretion standard. The Hinkson court adopted a two-part test that appellate courts should follow to make an objective determination as to whether a district court abused its discretion in applying a rule of law to the facts in denying a motion for a new trial. Although accompanied by a vigorous dissent, the Hinkson abuse-of-discretion test has quickly become a powerful influence and has been widely cited throughout the circuit.
William B. Jones,
What's the Deference?: United States v. Hinkson Outlines a New Test For “Abuse of Discretion”, 40 Golden Gate U. L. Rev.