In the case of Darren J. Custis v. United States, 1993, Custis was convicted for being a felon in possession of a firearm and sentenced under the Armed Career Criminal Act (ACCA), which imposes mandatory minimum sentences on offenders with three prior convictions for violent felonies or serious drug offenses. He appealed his sentence arguing that two of his previous convictions were unconstitutional because he had not been represented by counsel during those proceedings. The Supreme Court held that defendants facing sentencing under ACCA could not challenge the validity of their previous state court convictions used to enhance their federal sentences unless they can show that they resulted from uncounseled proceedings where there was no waiver of counsel rights, as per Gideon v Wainwright ruling. The Court reasoned that allowing such challenges would burden the courts and disrupt finality in criminal proceedings without significantly advancing constitutional fairness goals.

In the dissenting opinion for Darren J. Custis v. United States, Justice Souter argued that the majority's decision was inconsistent with both precedent and principles of federalism. He contended that allowing a defendant to challenge prior state convictions during sentencing proceedings in federal court undermines state courts' authority and disrupts finality in criminal proceedings. Furthermore, he pointed out that Congress had not explicitly provided defendants this right when it enacted the Armed Career Criminal Act (ACCA). Instead, he believed Congress intended for defendants to use existing procedures within state courts or habeas corpus petitions to challenge their previous convictions if they were unconstitutional or otherwise invalid. Therefore, according to Justice Souter’s dissenting view, such challenges should not be permitted during federal sentencing hearings under ACCA.