Justice Sotomayor concluded with the following in relevant part: Simmons specified the legal materials that were unavailable: the “‘Rules Governing 2255 Proceedings and the Antiterrorism and Effective Death Penalty Act of 1996 statute of limitations,’” as well as any “‘federal Law Library.’” Id., at 793. And he explained that this lack of access “‘prevented him from having the ability to timely pursue and know the timeliness for filing a 2255 Motion.’” Ibid. Little “liberal construction” is required to understand this as pleading causation: Simmons alleged that his inability to access habeas law materials prevented him from understanding how and when to file a habeas petition, and therefore from filing. See Lewis, 518 U. S., at 351 (noting that an inmate could plead a violation of right of access to the courts because he “suffered arguably actionable harm that he wished to bring before the courts, but was so stymied by inadequacies of the law library that was unable even to file a complaint”).
As this Court has repeatedly stressed, “‘a pro se complaint, however inartfully pleaded, must be held to less stringent standards than formal pleadings drafted by lawyers.’” Erickson v. Pardus, 551 U. S. 89, 94 (2007) (per curiam) (summarily reversing where a pro se complaint was dismissed “on the ground that petitioner’s allegations of harm were too conclusory to put these matters in issue”). These liberal construction requirements for pro se litigants carry particular weight when courts consider habeas filings, given that “the writ of habeas corpus plays a vital role in protecting constitutional rights.” Slack v. McDaniel, 529 U. S. 473, 483 (2000). A petitioner’s failure to explain causation adequately may be proper cause for the court to provide clear guidance and an opportunity to remedy, or to hold an evidentiary hearing to determine the relevant facts, as other Circuits have required in similar circumstances. See, e.g., Estremera v. United States, 724 F. 3d 773, 777 (CA7 2013). It is rarely a reason to find a pro se habeas petition time barred on the pleadings. I trust the courts of appeals will do so only where our liberal pleading standards warrant such a harsh result.
Part of the dissent’s concern likely involved the perverse motivation that the majority’s decision to deny certiorari provides to prison authorities. Prisons could benefit from their failure to maintain research materials by a decrease in habeas petitions and a related in increase in the prison population.