Whether the cross-appeal rule is a jurisdictional rule, a mandatory claim-processing rule, or an informal and flexible rule in civil cases

QUESTION PRESENTED “(I]t takes a cross-appeal to justify a remedy in favor of an appellee.” Greenlaw v. United States, 554 U.S. 237, 244-245 (2008). This is an “inveterate and certain” rule, and “in more than two centuries of repeatedly endorsing the cross-appeal requirement, not a single one of [this Court’s] holdings has ever recognized an exception to the rule.” Jd. at 245. But some of the lower courts have. The lower courts “debate whether lack of a cross-appeal deprives the court of appeals of jurisdiction’ to modify the judgment at the behest of the appellee,” or “whether the requirement can be put aside entirely if that seems just.” 15A Charles Alan Wright, Arthur R. Miller & Edward H. Cooper, Federal Practice and and Related Matters § 3904 (3d ed. 2024 update). “The cases are in disarray.” Id. The question presented is: Whether the cross-appeal rule, as applied in civil cases, is a jurisdictional rule that courts must apply (as the First, Second, Fourth, Fifth, and Tenth Circuits have held), a mandatory claim-processing rule that yields only to a party’s waiver or forfeiture of its protections (as the Sixth, Eleventh, and Federal Circuits have held), or an informal and flexible rule that yields to any court-crafted exception (as the Third, Seventh, Eighth, Ninth, and D.C. Circuits have held).