979 F.3d 766
9th Cir.2020Background
- Defendant Bacon proffered expert testimony; the district court excluded it as irrelevant under Daubert and Federal Rule of Evidence 702 without assessing reliability.
- A three-judge panel reversed, holding the district court applied an incorrect Daubert relevance standard and that the error was not harmless.
- The panel followed Ninth Circuit precedent (Mukhtar/Barabin/Christian) and vacated the conviction, ordering a new trial.
- A unanimous concurrence urged conditional vacatur and a limited remand to let the district court first decide admissibility (to avoid unnecessary retrial if testimony would still be excluded on reliability grounds).
- The en banc court considered whether a bright-line mandatory-retrial rule should govern when a Daubert error occurs but the record leaves open other admissibility grounds.
- The en banc court held that appellate panels have discretion under 28 U.S.C. § 2106 to craft remedies "as may be just under the circumstances," overruled prior Ninth Circuit mandatory-retrial precedent to the extent inconsistent, and remanded to the three-judge panel to choose the appropriate remedy in this case.
Issues
| Issue | Bacon's Argument | Government's Argument | Held |
|---|---|---|---|
| Proper remedy when a district court commits a non-harmless Daubert error but the record is unclear whether admission/exclusion would stand on other grounds | Conditionallly vacate and remand to district court to decide admissibility first (avoid needless retrial) | Follow circuit precedent requiring vacatur and a new trial | Appellate panels have discretion under §2106 to fashion the remedy case-by-case; no mandatory retrial rule |
| Whether prior Ninth Circuit precedent requires automatic retrial for any non-harmless Daubert error | Precedent is misguided; treat Daubert errors like other evidentiary errors and permit limited remand | Precedent (Mukhtar, Barabin II, Christian) mandates retrial to protect gatekeeping | Overruled prior cases to the extent they impose a per se retrial rule; panels may choose remedies based on circumstances |
| Whether an appellate court may itself resolve admissibility when the record suffices | Prefer limited remand to district court but accepts appellate findings if record is adequate | May rely on precedent but sometimes appellate resolution is appropriate | Court reaffirmed that appellate courts may make admissibility and reliability findings if the record is sufficient and then enter appropriate relief |
| Whether Daubert errors warrant special remedial treatment distinct from other evidentiary errors | Daubert errors should not be treated differently; use ordinary appellate remedial tools | Special rule promotes Daubert gatekeeping and prevents post-hoc rationalization | Court rejected a special remedial category for Daubert errors and restored ordinary appellate discretion |
Key Cases Cited
- Daubert v. Merrell Dow Pharms., 509 U.S. 579 (1993) (establishes trial-court gatekeeping role for expert testimony under Rule 702)
- Mukhtar v. Cal. State Univ., Hayward, 319 F.3d 1073 (9th Cir. 2003) (prior Ninth Circuit decision requiring retrial when Daubert reliability finding was omitted)
- Barabin v. AstenJohnson, Inc., 700 F.3d 428 (9th Cir. 2012) (panel applying Mukhtar rule; later reheard en banc)
- Barabin v. AstenJohnson, Inc., 740 F.3d 457 (9th Cir. 2014) (en banc decision reaffirming Mukhtar and endorsing mandatory-retrial approach)
- United States v. Christian, 749 F.3d 806 (9th Cir. 2014) (applied mandatory-retrial rule in criminal context after erroneous exclusion of diminished-capacity expert testimony)
- United States v. Ray, 956 F.3d 1154 (9th Cir. 2020) (panel opinion in this matter that vacated and remanded for a new trial; prompted en banc review)
- United States v. Redlightning, 624 F.3d 1090 (9th Cir. 2010) (explains that trial judge must assess both relevance and reliability under Rule 702)