6 MOORE v. HARPER THOMAS, J., dissenting injury to petitioners by doing anything to it. Whether we accept or reject petitioners’ Elections Clause defense, plaintiffs-respondents’ claims remain dismissed. As far as this case is concerned, there simply is nothing this Court could decide that could make any difference to who wins or what happens next in any lower court. That is the definition of mootness for an appellate proceeding. The United States understands this. See Supplemental Letter Brief for United States as Amicus Curiae 3 (May 11, 2023) (“[T]he question this Court granted certiorari to decide is now moot because the Court’s resolution of that question could not affect the disposition of this case”). So do the elections officials whose conduct Harper I once enjoined. Supplemental Brief for State Respondents 1 (May 11, 2023) (“[T]his case is moot”). So, too, do the plaintiffs-respondents who started this case in the first place. See Letter Brief for North Carolina League of Conservation Voters, Inc., et al. 2 (May 11, 2023) (“The North Carolina Supreme Court’s February 2022 judgment reversing the same January 11, 2022 trial-court judgment that the North Carolina Supreme Court just affirmed is now a nullity”); Supplemental Letter Brief for Rebecca Harper et al. 1 (May 11, 2023) (“Petitioners have won a full victory in state court”). As one group of plaintiffs-respondents put it, “there is no non-frivolous basis for jurisdiction here.” Ibid. B The majority does not contest that the Elections Clause issue in this case was only a defense to plaintiffsrespondents’ claims for relief. Nor does it deny that Harper III overruled Harper I and affirmed the very same trialcourt judgment that Harper I had reversed. And it concedes that, as a result, plaintiffs-respondents’ claims have been dismissed in full on state-law nonjusticiability grounds. Thus, the majority does not contend that its opinion on the