The United States Supreme Court ruled today against six states that sought standing to sue sources of greenhouse gas emissions for their contributions to global warming under federal common law. The court ruled 8–0 in American Electric Power Co. v. Connecticut that the Clean Air Act and the Obama administration’s regulatory actions on climate had displaced the states’ common law “public nuisance” argument. The Court left one issue open, splitting 4–4 on the issue of whether federal courts even had jurisdiction to hear the claims.