Former Attorney General Bill Barr hopes the U.S. Supreme Court will quickly decide that climate change lawsuits filed by blue-state politicians against energy companies are a federal, not a state issue.
“It’s clear that the Clean Air Act does not give the state this power,” Barr said after a discussion on Energy Security, Innovation & the Rule of Law hosted by Meet the Future at the National Press Club.
Oral arguments in Suncor Energy v. County Commissioners of Boulder County are scheduled for Oct. 5, the opening day of the Supreme Court’s new term. The justices will consider whether federal law preempts state-law claims seeking damages for injuries allegedly caused by interstate and international greenhouse gas emissions.
The court has also directed the parties to address a preliminary question: whether the justices have statutory and constitutional jurisdiction to hear the case before the Colorado litigation reaches a final judgment.
“I think the Supreme Court was a little late in coming in on this issue because it is so fundamental,” Barr said. “But I’m glad they granted cert because this really has to be addressed and dealt with quickly.”
The lawsuit was filed in 2018 by Boulder County and the city of Boulder as part of a wave of litigation brought by Democratic-led states and local governments against energy companies, including Exxon Mobil, Chevron, BP and ConocoPhillips.
Boulder alleges that Suncor and Exxon Mobil misled the public about the climate effects of fossil fuels while continuing to produce, promote and sell them. It is seeking compensation for past and future costs associated with wildfires, flooding, drought and other alleged consequences of climate change.
Barr said the potential financial exposure extends far beyond the Boulder lawsuit.
“They’re seeking to impose hundreds of billions of dollars and more on the energy industry in the United States,” Barr said.
He cited lawsuits filed by Puerto Rican municipalities seeking approximately $100 billion in connection with the damage caused by Hurricane Maria. Those cases were dismissed in 2025, largely on statute-of-limitations grounds, and are being appealed.
Barr also pointed to a 2025 study published in Nature that estimated carbon dioxide and methane emissions attributed to 111 companies caused $28 trillion in global economic losses from extreme heat between 1991 and 2020. The study’s authors presented their research as a potential framework for assigning climate liability to individual companies.
“Basically, it’s open-ended,” Barr said of the potential damages.
The legal strategy of using local nuisance, trespass, and fraud laws against global energy companies has not been very successful. While the Colorado and Hawaii cases have proceeded, judges in other states – including California, New York, and Maryland – have rejected the arguments. Other claims have been dismissed in Puerto Rico and South Carolina.
Critics have called the strategy “lawfare,” saying that climate activists and political allies are attempting to use courts to set national climate policy instead of leaving those decisions to Congress or the Environmental Protection Agency.
Barr said the lawsuits conflict with the constitutional relationship among the states.
“The whole idea of a federal union is that states surrender some part of their sovereignty to one overarching national government,” Barr told InsideSources. “If one state starts interfering in another, they’ve given up their right to do what they would have done before the union, which is use force against the state that’s interfering.”
Republicans in the U.S. Senate agree. In an amicus brief filed with the Supreme Court, U.S. Sens. Ted Cruz of Texas, Mike Lee of Utah, Chuck Grassley of Iowa and Ted Budd of North Carolina argued that federal common law and the Clean Air Act give the federal government authority over interstate emissions.
Twenty-six states have filed a separate brief supporting the energy companies, arguing that Colorado cannot use its law to regulate conduct occurring within their borders.
Legal scholars, including University of Virginia law professor Saikrishna Prakash, have made similar arguments.
Prakash said the Suncor case hinges on whether Colorado can effectively regulate global oil and gas production by attaching legal liability to it.
“It implies that New York City, Pensacola, Florida, Anchorage, Alaska, you know, Boulder, Idaho, they can regulate the entire United States because of the effects that are felt within their jurisdictions, and then they can go further and regulate the entire world,” he said during a recent webinar hosted by the Law & Economics Center at George Mason University’s Scalia Law School.
Boulder rejects that characterization. Its attorneys argue the lawsuit does not seek emissions restrictions, an injunction against fossil-fuel production or authority over conduct in other states.
Instead, Boulder says it is seeking damages for allegedly deceptive marketing and other conduct traditionally covered by state tort and consumer-protection laws. Its attorneys argue that the Clean Air Act regulates emissions from specific sources but does not regulate the production, sale or marketing of fossil fuels.
“Avoiding liability would not require reducing emissions at all — only telling the truth, so the public can make informed consumption decisions free of the distorting effect of petitioners’ misrepresentations,” Boulder’s attorneys wrote in their Supreme Court brief.
The energy companies and their supporters rely heavily on the Supreme Court’s unanimous 2011 ruling in American Electric Power v. Connecticut. In that case, the court held that the Clean Air Act displaced federal common-law claims seeking court-ordered reductions in carbon dioxide emissions from power plants.
“[The justices] said using the state law would be inappropriate. These are issues of special federal interest and legislative interest,” said Phil Goldberg, a former Democratic House staffer now with the law firm Shook, Hardy & Bacon. “They said it straight out.”
The 2011 ruling did not, however, decide the precise question now before the court. The justices expressly left open whether the Clean Air Act preempts claims brought under state law because that issue had not been fully briefed.
Barr said allowing state lawsuits to proceed would give courts policymaking authority that properly belongs to elected officials.
“The body politic has not decided to destroy our fossil fuel industry,” Barr said. “It is still the foundation of prosperity in the world, and we need it now. For them to try to be destroying it when they can’t get that through the political process, using courts, is what’s at stake here.
“I’m hopeful the Supreme Court will do the right thing,” Barr said.
Taylor Millard writes about politics and public policy. He wrote this for InsideSources.com.
