American Electric Power v. Connecticut

New York City and eight states brought a claim against five major electric power companies, alleging that their greenhouse gas emissions constituted a public nuisance. The claim rested primarily on federal common law nuisance; plaintiffs also brought secondary claims under state tort law. (The Supreme Court ultimately did not address the issue of displacement of state tort law, and no other plaintiff has brought such a case.) The district court originally dismissed the case on Political Question Doctrine grounds. After years of delay, the Second Circuit reversed the motion to dismiss, finding that standing had been met and that the Clean Air Act had not entirely displaced federal common law.

There two issues in the Supreme Court were: (1) Whether the plaintiffs had standing to bring their claims under Massachusetts v. EPA, 549 U. S. 497 (2007); and (2) Whether the Clean Air Act displaced federal common law nuisance actions to force greenhouse gas emitters to abate their emissions. On the first question, an equally divided court (4–4) affirmed the Second Circuit’s grant of standing under the logic of Massachusetts v. EPA. One the second question, the Court ruled 8­–0 (with Justice Sotomayor recused) that the Clean Air Act displaced federal common law of nuisance related to air pollution. The Court concluded that, unlike displacement of state law, “[l]egislative displacement of federal common law does not require the ‘same sort of evidence of a clear and manifest [congressional] purpose’ demanded for preemption of state law.” American Electric Power, 564 U.S. 410, 423 (2011) (quoting Milwaukee v. Illinois, 451 U. S. 304, 317 (Milwaukee II) (addressing displacement of federal common law by the Clean Water Act)). The parties to this case ultimately abandoned their state tort claims below. To our knowledge, no state has pursued a state tort action to gauge whether state tort suits are similarly displaced by the Clean Air Act.

Citation: American Electric Power v. Connecticut, 564 U.S. 410 (2011)

Key Documents:

• Decision
• Petitioners’ Brief
• States’ Brief