Did the Sixth Circuit violate Fed. Rule Civ. P. 52(a)(6) when it failed to apply the proper, heightened and deferential standard to the district court's expert witness credibility determination?

Question Presented Respondent Johnny Phillips was convicted of wanton murder for shooting Phillip Glodo in the back of the head. Phillips filed a petition for federal habeas relief in district court claiming the state violated Brady v. Maryland, 373 U.S. 83 (1963), by failing to provide in discovery an autopsy x-ray of Glodo’s skull. The district court conducted an evidentiary hearing to determine whether the x-ray was favorable and material to Phillips’s defense and therefore subject to disclosure under Brady. Two expert witnesses testified at the hearing about the significance of the x-ray. Phillips’s expert was Larry Dehus, a forensic scientist and ballistics expert, and the Warden’s expert was Dr. Jennifer Schott, the medical examiner who conducted Glodo’s autopsy. The district court did not find Dehus’s testimony about the significance of the x-ray reliable, and chose instead to rely on Dr. Schott’s testimony. Based upon its findings, the district court rejected Phillips’s claim that the autopsy x-ray was favorable and material under Brady. A divided panel of the United States Court of Appeals for the Sixth Circuit reversed the district court, giving no meaningful deference to the district court’s expert witness credibility determination. And, it adopted an entirely new standard, holding that the district court should have credited the testimony of Phillips’s expert merely because that testimony was not “blatantly self-serving or dishonest.” Phillips v. Valentine, 826 F. App’x 447, 460 (6th Cir. 2020). Applying that novel standard, the Sixth Circuit found that the autopsy x-ray was in fact favorable and material to Phillips’s defense, and therefore should have been disclosed to Phillips in discovery. i The Sixth Circuit reached this conclusion based on nothing more than the expert testimony that the district court rejected as unreliable. The questions presented are as follows: (1) Did the Sixth Circuit violate Fed. Rule Civ. P. 52(a)(6) when it failed to apply the proper, heightened and deferential standard to the district court’s expert witness credibility determination? (2) Did the Sixth Circuit usurp the district court’s expert witness gatekeeping function when it held that the district court should have credited the testimony of Phillips’s expert—and granted Phillips’s petition—simply because that testimony was not blatantly self-serving or dishonest? ii Statement of