3. Can the court, sua sponte, consider a defense that defendant has failed affirmatively to plead? In DAY v. McDONOUGH, 547 U.S. 198, 126 S.Ct. 1675, 164 L.Ed.2d 376 (2006), the Supreme Court held that district courts may but are not required to raise sua sponte the timeliness of a state prisoner’s habeas petition when the state defendant has failed to raise the limitations period as an affirmative defense. To mitigate any unfairness, the Court further held that the district court is required to give the parties fair notice and an opportunity to present their positions on why the limitations period should not yield dismissal. Should this practice extend to defenses that do not have systemic implications for the justice system?