In the case of Antonio Tonton Slack v. Eldon McDaniel, Warden et al., 1999, Slack was convicted for drug offenses and sentenced to prison in Nevada. He filed a federal habeas corpus petition challenging his conviction but it was dismissed as time-barred under the Antiterrorism and Effective Death Penalty Act (AEDPA). The Ninth Circuit Court of Appeals affirmed this dismissal. However, when he appealed again with new evidence suggesting innocence, the Supreme Court held that if a prisoner's state post-conviction relief is denied on procedural grounds instead of merit-based ones and they file a federal habeas petition within one year from that denial date, then their application should not be considered untimely under AEDPA rules. Furthermore, if such an application includes claims which were previously unadjudicated due to procedural default at state level but are now substantial enough to warrant further proceedings or investigation by district courts based on newly discovered evidence or constitutional error affecting trial fairness etc., then these claims can also proceed along with others in same application without being subject to second-or-successive restrictions imposed by AEDPA.

The dissenting opinion in the case of Antonio Tonton Slack v. Eldon McDaniel, Warden et al., argued that a federal habeas corpus petition should not be considered "second or successive" if it raises claims that were dismissed for failure to exhaust state remedies in an earlier filed petition. The dissenters believed this interpretation was consistent with the text and purpose of the Antiterrorism and Effective Death Penalty Act (AEDPA). They also contended that treating such petitions as second or successive would unfairly penalize prisoners who follow court instructions to dismiss their unexhausted claims and return to state court. Furthermore, they disagreed with majority's view on procedural default rule application which could lead to unjust results by barring consideration of certain constitutional claims due to technicalities rather than merit.