Mullin v. Al Otro Lado · ¶177

Article III’s limits apply throughout the entirety of a dispute, not just at its outset. Thus, a case or controversy “must be extant at all stages of review, not merely at the time the complaint is filed.” Alvarez v. Smith, 558 U. S. 87, 92 (2009) (internal quotation marks omitted). Federal courts lack jurisdiction over cases that become “moot” during the course of litigation because “the issues presented are no longer live or the parties lack a legally cognizable interest in the outcome.” Chafin v. Chafin, 568 U. S. 165, 172 (2013) (internal quotation marks omitted). By insisting on the continued existence of a “live controversy,” our mootness rules ensure that we do not issue “advisory opinions on abstract propositions of law.” Hall v. Beals, 396 U. S. 45, 48 (1969) (per curiam).

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