Law and Facts on appeal
In general, courts of appeal defer to trial courts on questions of fact. In contrast, questions of law—like explaining what a statute (law) means—are reviewed without deference to what the trial court decided.
Facts: If the court of appeals disagrees with a trial judge about a factual issue—like whether a police officer saw a possible drug transaction before stopping someone to search them—the court of appeals will assume that the trial court got that finding correct.
Law: But when it comes to what a law means, the appellate court will decide the issue without giving the trial court’s interpretation any special weight. Court of appeals decisions bind the trial court. Indeed, a court of appeals decision is the rule not only for that case, but for future cases as well: the decision becomes precedent that trial courts must follow.
Facts and Law: The world is not a tidy place, and many issues involve both facts and law. For instance, there is a rule of evidence, 404(b), that limits the use of “other crimes, wrongs, or acts.” The court of appeals will review “de novo”, or without deference, whether evidence is covered by Rule 404(b).
If the court of appeals decides, as a matter of law, that the evidence is covered by Rule 404(b), it then reviews the use of this evidence at trial for abuse of discretion.
And there is one more step: even if the trial court was wrong to allow the other acts evidence to be used, the court of appeals will only reverse the trial court’s decision if the error was not “harmless.”
The Ninth Circuit case of a kidnapping shows how this works. United States v. Carpenter, 923 F.3d 1172, 1180 (9th Cir. 2019).
The district court had allowed the jury to hear evidence of a codefendant’s methamphetamine use. Since that drug use was not part of the crime the defendant was charged with, the court of appeals held, as a matter of law, that the drug use was “other acts” evidence under Rule 404(b).
Next, the court of appeals found that the district court abused its discretion by allowing the jury to hear the evidence of drug use.
Finally, however, the court of appeals determined that the district court’s error was harmless. According to the court of appeals, there was so much other evidence of the defendant’s guilt that the mistakes the district court made did not change the outcome.
Carpenter won two battles but lost the war: the error in the trial court was found to be harmless.