## Facts

- Wichita police responded to a residential disturbance and observed a black plastic gun case inside a vehicle occupied by Dale L. Adams and another person.
- An officer determined the case contained an assault-style 9mm semiautomatic pistol.
- Adams told police that both the vehicle and the firearm belonged to him; the officer seized the weapon and arrested Adams.
- After receiving Miranda warnings, Adams made detailed incriminating statements that he recently purchased the gun, kept it at his home, and brought it to the vehicle that day.
- At trial, Adams recanted and testified he had lied to police to protect his girlfriend.
- The defense sought to introduce a psychologist’s written report suggesting Adams’s psychological traits made him prone to making false or unreliable statements; the district court refused to admit the report or related expert testimony.
- A jury convicted Adams of being a felon in possession of a firearm under 18 U.S.C. § 922(g)(1), and he was sentenced to 51 months’ imprisonment plus three years’ supervised release.

## Issues

1. Whether excluding the psychologist’s report and related expert testimony under Federal Rule of Evidence 702 (and related constitutional principles) improperly prevented Adams from presenting a defense by explaining why his post-arrest statements were false.
2. Whether 18 U.S.C. § 922(g)(1), as applied, exceeds Congress’s authority under the Commerce Clause.

## Decision

- The court affirmed the conviction and sentence.
- The district court did not abuse its discretion in excluding the psychologist’s report and related expert evidence under Rule 702 because it would not assist the jury and largely amounted to credibility bolstering.
- Exclusion of the evidence did not violate due process or the right to present a defense because Adams could present his theory through his own testimony and the excluded material was properly barred by ordinary evidentiary limits.
- The court rejected the Commerce Clause challenge and upheld § 922(g)(1) as a valid exercise of congressional authority where the statute’s interstate-commerce nexus is satisfied.

## Legal Principles

- Expert testimony is admissible under Federal Rule of Evidence 702 only if it is relevant and will assist the trier of fact; evidence that does not add to jurors’ common ability to assess a dispute may be excluded.
- Expert evidence that effectively tells the jury whom to believe, or that primarily supports a witness’s truthfulness, intrudes on the jury’s exclusive role in making credibility determinations and may be excluded.
- Proper application of standard evidentiary rules to exclude marginally helpful, credibility-focused expert testimony ordinarily does not violate due process or the constitutional right to present a defense.
- 18 U.S.C. § 922(g)(1) is constitutional under the Commerce Clause when the required connection to interstate commerce is shown (including proof that the firearm traveled in interstate commerce).

## Conclusion

The Tenth Circuit held that the district court permissibly excluded a psychologist’s report offered to suggest the defendant was predisposed to make false statements because it did not meaningfully aid the jury and improperly targeted credibility, and it further upheld the felon-in-possession statute against a Commerce Clause challenge, affirming Adams’s conviction and sentence.


United States v. Adams, 271 F.3d 1236 (10th Cir. 2001)