In Sackett v. United States (Sackett II), the Supreme Court narrowed the scope of federal jurisdiction under the Clean Water Act. In doing so, Justice Alito's opinion for the Court adopted the interpretation of the CWA articulated in Justice Scalia's four-justice plurality from Rapanos v. United States, and rejected the "significant nexus" test articulated in Justice Kennedy's concurrence. This was significant because, for over fifteen years, the federal government, and most lower-courts, had embraced Justice Kennedy's opinion as the controlling opinion. As the 1 in the Court's 4-1-4 split, Justice Kennedy's opinion was understood as embodying the narrowest grounds under Marks v. United States.
While most viewed Justice Kennedy's opinion as articulating the outer bounds of federal regulatory jurisdiction under Rapanos, that was not how the case was presented to the Court, and none of the justices viewed that opinion as a controlling precedent. Wrote Justice Alito in footnote 3 of his opinion for the Court: "Neither party contends that any opinion in Rapanos controls. We agree."
While Justices Kavanaugh and Kagan disagreed strongly with Justice Alito's embrace of the Scalia plurality, neither contended that the Court was obligated to follow the Kennedy concurrence under principles of stare decisis. They objected to the substance of the Alito majority, not its treatment of Justice Kennedy's Rapanos opinion.
