In the 1987 case of Frederick Mathews v. United States, the Supreme Court ruled on whether a defendant's Sixth Amendment right to counsel was violated when his attorney failed to object to an incorrect jury instruction regarding intent in a mail fraud case. The court held that there was no violation because even if the lawyer had objected and received a correct instruction, it would not have changed the outcome of the trial due to overwhelming evidence against Mathews. Therefore, this failure did not constitute ineffective assistance of counsel under Strickland v. Washington (1984), which requires showing both deficient performance by counsel and prejudice as a result thereof.

In the dissenting opinion for Frederick Mathews v. United States, Justice Thurgood Marshall argued that the majority's decision was a departure from established precedent and an unnecessary expansion of federal power. He contended that Congress did not intend to make it a separate crime to use or carry firearms during drug trafficking crimes when they enacted 18 U.S.C §924(c). Instead, he believed this provision was meant only as a sentencing enhancement for those already convicted of such offenses. Furthermore, he criticized the majority’s interpretation as overly broad and warned it could lead to absurd results where minor involvement with firearms would result in severe penalties. He also expressed concern about potential double jeopardy issues arising from multiple punishments for essentially the same conduct under different statutes.