Doctor David Pon is a highly experienced and credentialed ophthalmologist who developed a new technique for treating wet macular degeneration (WMD) that involved a low-powered laser technique that, he claimed, did not leave visible scars the way conventional treatments do. Dr. Pon was indicted for Medicare fraud on the premise that he falsely diagnosed patients with WMD and then billed the government for laser treatments that were not rendered or were not effective. Fourteen witnesses testified that Dr. Pon successfully treated them for WMD, as did Dr. Pon himself; accordingly, the case largely boiled down to a battle of credibility between the prosecution’s witnesses and the defense witnesses, including particularly Dr. Pon himself.

During the rebuttal phase of the trial, prosecutors elicited testimony from one of the defense witnesses that Dr. Pon performed 52 surgeries on his blind eye but then successfully objected to Dr. Pon’s effort to fully explain his reasons for performing each of those surgeries, which, according to Dr. Pon, was to protect the patient’s remaining good eye. The prosecution then suggested to the jury that Dr. Pon had no explanation for performing 49 of those 52 surgeries, when in fact the prosecution knew that Dr. Pon did have an explanation but that an erroneous evidentiary ruling by the trial court had prevented him from testifying about it.

The issue on appeal was whether the trial court’s error, which “shredded” Dr. Pon’s credibility, was sufficiently prejudicial to warrant a new trial. Examining that question only from the perspective of the government’s case—and not considering the effect of the error on the defendant’s case—a divided panel of the Eleventh Circuit held that the trial court’s error in limiting Dr. Pon’s rebuttal testimony was harmless and affirmed his conviction.

The question presented in Dr. Pon’s cert petition is whether a trial error may be considered harmless based on the government’s “overwhelming evidence of guilt” without considering the potential effect of that error on the jury’s view of the of the defendant’s case, including the defendant’s credibility.

The Cato Institute has joined the Florida Association of Criminal Defense Lawyers on a brief supporting Dr. Pon’s petition to the Supreme Court. We argue that the Eleventh Circuit erred by failing to fully appreciate the nature and significance of the Sixth Amendment right to a jury trial, which includes the ability to present sufficient evidence both to preserve the defendant’s own credibility and to offer the jury a competing narrative framework though which to view the evidence presented by the prosecution. We also note the risk of hindsight bias when an appellate court reviews a cold trial record knowing that the jury voted to convict the defendant—albeit on an incomplete presentation of the evidence, as occurred in this case. Allowing such verdicts to stand on the dubious premise that the trial court’s error was, in retrospect, “harmless” creates perverse incentives for judges and prosecutors to be less scrupulous than they might otherwise be and further dilutes the value of an institution—the criminal jury trial—that plays an increasingly marginal role in a system where more than 97 percent of convictions are obtained through an often breath-takingly coercive plea-bargaining process.