In the case of Khanh Phuong Nguyen v. United States et al., 2002, the U.S Supreme Court ruled that a federal appellate panel's decision remains valid even if one judge on the panel was not constitutionally appointed. The petitioner, Khanh Phuong Nguyen, had been convicted for drug-related offenses and deported from the U.S. He appealed his deportation order arguing that Judge William Fletcher who sat on his Ninth Circuit appeal panel was unconstitutionally appointed because he served alongside his mother, Judge Betty Binns Fletcher which violated a law prohibiting relatives from serving together in certain public offices. However, Justice David Souter writing for an 8-1 majority held that although it was unconstitutional to have two family members serve simultaneously on the same court bench under Title 28 USC Section 458 (a nepotism statute), this did not invalidate decisions made by such panels as long as they were otherwise competent and their decisions fair.

In the dissenting opinion for Khanh Phuong Nguyen v. United States, Justice Scalia argued that a federal appellate panel must consist of three Article III judges and any deviation from this requirement invalidates the judgment. He disagreed with the majority's view that harmless-error analysis could be applied to structural errors in court composition, asserting it undermined constitutional protections. Scalia contended that allowing non-Article III judges on panels would open up possibilities for other non-constitutional entities or individuals to participate in federal judicial decision-making processes, which he believed was fundamentally wrong and unconstitutional. He also pointed out inconsistencies within the majority’s argument regarding when an error can be deemed “harmless”. In his view, if such an error occurred at trial level it wouldn’t have been considered harmless but is being treated differently at appellate level without clear justification.