Whether a Confrontation Clause error can ever be harmless when an accused is prevented from cross-examining the key government witness—a witness who serves as the sole evidence against the accused—about his bias and motive to lie?

Question Presented Petitioner Orlando Burgos was deprived of his Confrontation Clause right to cross-examine his accuser—the key prosecution witness—that he received a benefit for his testimony: a U-Visa. That Confrontation Clause violation was undisputed below; the only remaining question was prejudice. When assessing that prejudice, as this Court has explained, courts must assume that the damaging potential of the crossexamination was fully realized. Courts must then apply various factors that look to the centrality of the witness to the prosecution’s case. These factors suggest that when an accused is prevented from crossexamining his accuser, and that accuser was the primary or sole evidence of guilt, a Confrontation error cannot be harmless. But the Ninth Circuit, in a published decision below, held that it was harmless. That opinion did not assume the damaging potential of the cross-examination was fully realized, and to the contrary, it imagined reasons to believe the witness. It also ignored that this witness’s testimony was the prosecution’s sole evidence of guilt. In other words, despite the witness being the sole evidence of guilt, the Confrontation Clause error was harmless. Therefore, the question presented is: Whether a Confrontation Clause error can ever be harmless when an accused is prevented from cross-examining the key government witness—a witness who serves as the sole evidence against the accused—about his bias and motive to lie?