特纳诉美国案

Jessie James Turner, Jr., a convicted felon, was indicted for possessing three firearms on November 8, 2018, in violation of 18 U.S.C. § 922(g)(1). At trial, Turner asserted three affirmative defenses: insanity, public authority, and entrapment. The Government called forensic psychologist Dr. Rebecca Barnette, who testified that Turner was "not unable" to appreciate the wrongfulness of his acts. Over Turner's objection, the district court admitted this testimony. The jury found Turner guilty, and he was sentenced to ten years in prison. Turner appealed, arguing the expert testimony violated Federal Rule of Evidence 704(b), which prohibits expert witnesses in criminal cases from opining on whether a defendant had a mental state constituting an element of a defense.

The Eleventh Circuit Court of Appeals held that the district court abused its discretion in admitting the expert testimony. However, applying Rule 52(a) of the Federal Rules of Criminal Procedure, the court ruled the error was harmless because it did not affect Turner's substantial rights. Turner's conviction was affirmed.

Whether the district court abused its discretion by admitting expert testimony from a forensic psychologist who opined on Turner's ability to appreciate the wrongfulness of his acts, in violation of Federal Rule of Evidence 704(b), and whether such error was harmless.

The case reaffirmed the strict limitation of Federal Rule of Evidence 704(b) on expert testimony regarding a defendant's mental state in criminal trials. It also demonstrated the Eleventh Circuit's application of the harmless error doctrine, showing that even when a district court abuses its discretion in admitting improper expert testimony, the conviction may still stand if the error did not substantially sway the jury's judgment.