The ruling reversed a New York federal appeals court, which in 2009 said the case could go forward.
The justices said the Environmental Protection Agency was better suited than federal judges to assess the costs and benefits of reducing carbon emissions.
The six states filed suit in 2004 and argued the utility companies were a public nuisance because their emissions contribute to global warming. The lawsuit was filed by the states in response to the U.S. Environmental Protection Agency (EPA) not taking action on national regulations for emissions reductions. The lawsuit invoked both state and federal law. The Supreme Court decision focused on the federal law claim and the justices said they weren’t ruling on the state law question.
The court, in an opinion written by Justice Ruth Bader Ginsburg, ruled the states cannot use federal public-nuisance law to seek court-imposed limits on emissions. The plaintiff states were Connecticut, New York, California, Iowa, New Jersey, Rhode Island, Vermont and Wisconsin. New York City and three land trusts were also plaintiffs in the case.
"The Clean Air Act entrusts such complex balancing to EPA in the first instance, in combination with state regulators,” Justice Ginsburg wrote in her decision.
Defendant utilities were American Electric Power Co. (NYSE: AEP), Southern Co. (NYSE: SO), Xcel Energy Inc. (NYSE: XCL), the federal government-owned Tennessee Valley Authority (NASDAQ: TVE) and Cinergy Corp.(NYSE: CIN), which was acquired by Duke Energy Corp. in 2006. The Obama administration joined the power industry in urging rejection of the suit.
The plaintiffs also alleged state-law claims in their lawsuit, which the Supreme Court did not address in its opinion. The high court sent the case back to the lower courts to consider those issues.
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