In the 1992 case of William McNeil v. United States, the Supreme Court ruled that a federal prisoner must file a motion to vacate his sentence under section 2255 before he can petition for habeas corpus relief under section 2241. The petitioner, William McNeil, was convicted in federal court and sentenced to prison. He later filed a habeas corpus petition challenging his conviction on constitutional grounds but did not first seek relief through a motion to vacate his sentence as required by law. The district court dismissed his petition and the appellate court affirmed this decision. Upon reaching the Supreme Court, it upheld these rulings stating that prisoners must follow an established sequence of procedures when seeking post-conviction relief: they must first move in the sentencing court to vacate their sentences; if denied then appeal within that same system; only after exhausting these remedies may they file for habeas corpus relief.

In the dissenting opinion for William McNeil v. United States, Justice Blackmun argued that the majority's interpretation of federal law was too rigid and failed to consider its potential impact on defendants' rights. He contended that under their interpretation, a defendant who wished to challenge his conviction based on ineffective assistance of counsel would have only one year from the date of judgment in which to do so. This timeframe is often insufficient due to various factors such as delays in obtaining transcripts or other necessary records, lack of knowledge about legal rights and procedures by incarcerated individuals without access to legal advice, among others. Furthermore, he pointed out that this could lead some defendants into filing premature habeas corpus petitions before fully developing their claims just out of fear they might otherwise lose an opportunity for relief altogether - thus potentially undermining both judicial efficiency and fairness towards those accused.