American Electric Power Company, Inc. v. Connecticut

States, New York City, and land trusts (plaintiffs) sued major power companies (defendants) under federal common-law nuisance theory, seeking court-ordered caps on carbon-dioxide emissions from their power plants; the lower courts disagreed over whether the suit was justiciable, and the case reached the Supreme Court on whether the Clean Air Act displaced this federal common-law claim.

Whether a federal statute that addresses an issue central to a federal lawsuit preempts application of federal common law.