The Virginia Supreme Court heard arguments in Welch v. Commonwealth over whether a trial court erred in excluding proposed defense expert testimony that the defense says would have challenged the commonwealth firearms expert and possibly affected the jury's verdict.

Megan Shapiro, senior appellate attorney for the appellant, told the court the exclusion was a "fundamental constitutional error" and not harmless because the defense expert "would have said that the Commonwealth's expert opinions were not scientifically reliable," leaving the jury with a single, unrebudded scientific account identifying the defendant's gun as the murder weapon.

The case matters because the disputed expert testimony bore directly on the strongest piece of identity evidence in the prosecution's case, Shapiro said. She urged the court to weigh "the importance of the unrebudded evidence to the prosecution, the persuasiveness, nature, and extent of the unrebudded evidence," and whether the defense had other means to counter it.

During questioning, justices pressed both sides on the appropriate standard of review. Justice Kelsey quoted the court's own harmless‑error language and asked whether the exclusion should be judged by how it may have affected jurors' minds in the total setting. Chief Justice and other justices probed whether, even if one hypothetical juror relied on the firearms testimony, the remaining evidence would still render any error harmless under Virginia's nonconstitutional harmless‑error standard.

Catherine Adelphia, appearing for the Commonwealth, said the trial record and procedural history showed the defense proffer was insufficient and the trial court did not abuse its discretion in limiting further proffers. "His own actions and statements are the best evidence," Adelphia said, pointing to circumstantial facts the Commonwealth contends supported the verdict: the defendant's inconsistent statements about timing, an effort to arrange disposal of a gun, passing a Buckmark .22 to a relative on the day of the shooting, and possession of matching ammunition.

Adelphia and the chief justice exchanged over whether the defense had put the Commonwealth on adequate notice of its intended rebuttal expert and whether the trial court afforded multiple opportunities to proffer. Adelphia noted the trial was on its fourteenth day when the proffer issues arose and said defense counsel had declined to add further detail after recesses the court had allowed.

Shapiro emphasized that the defense was left without a "battle of the experts" on the central forensics question: whether the Commonwealth's expert testimony that the defendant's gun fired the fatal bullets could properly be described as reaching "practical certainty." She argued that a defense expert would have at least rendered that opinion scientifically contestable or inconclusive and that, under the court's harmless‑error rubric, the impact of the unchallenged expert testimony on jurors must be assessed in relation to the whole trial.

In rebuttal, Shapiro urged the justices to focus on the record and argued the exclusion could have affected the verdict where the forensic testimony stood as the single unrebudted scientific link between the defendant and the shootings. The parties agreed the jury deliberated multiple days at trial but disputed whether the remaining circumstantial evidence would have compelled the same result absent the excluded testimony.

No decision was announced from the bench. The court heard argument and questioned counsel; a written opinion will follow at a later date.