This morning, the Supreme Court rang in its new term by hearing oral argument in Suncor Energy v. County Commissioners of Boulder County. As I’ve previously discussed, the case involves an attempt by Boulder, Colo., to hold energy companies liable for alleged harms stemming from worldwide greenhouse gas emissions because of the companies’ fuel production around the world. Over nearly two hours of argument, several justices expressed doubt that Colorado law can extend that far.
According to Justice Kavanaugh, “a wall of precedent” stands in Boulder’s way. As he stated during the argument, it is “crystal-clear” under prior rulings “that interstate air and water pollution are matters for federal law unless Congress specifically preserves state law.” Those precedents are fatal to Boulder’s claims.
Precedent isn’t the only thing standing in the way of Boulder’s claims. Kannon Shanmugam, counsel for the energy companies, identified two interrelated constitutional doctrines that also bar Boulder’s suit: the equal sovereignty of the states and the territorial limits on the jurisdiction of state law. Both prevent Colorado from reaching across its borders into neighboring states to impose tort liability on lawful energy production occurring around the country and the globe.
Those principles are well grounded in Supreme Court precedent and founding-era sources. Shanmugam mentioned the excellent amicus brief filed by the State of Tennessee. That brief, along with others from Save Our States and Consumers’ Research, lays out the originalist footing for the doctrines. As I covered back in May, those three briefs articulate how the Constitution preserved states’ status as coequal sovereigns, ensuring that no one state within the Union could impose its laws on the rest. Multiple constitutional provisions reflect this core commitment, and early American legal treatises and Supreme Court decisions repeatedly affirmed it.
Boulder’s attorney, Kevin Russell, drew stern questions from Chief Justice Roberts, who characterized the suit as “an attempt to evade” the Court’s precedents on interstate air pollution. Rather than suing over carbon emissions — which would plainly be foreclosed under the Court’s precedents — Boulder asserts claims against energy producers, focusing its attention further upstream in the supply chain. But as Roberts noted, the alleged harm doesn’t come from the fuel production itself, but from greenhouse gas emissions all over the world. Ultimately, in the chief justice’s words, Colorado’s suit is “an effort to reduce emissions.” Indeed, one of Boulder’s attorneys previously conceded as much — Boulder’s suit and others like it are essentially “an indirect carbon tax,” and if allowed to proceed, they’d result in massive costs being passed along to consumers around the nation.
Justice Kagan also zeroed in on the fact that Boulder’s suit is an effort to regulate emissions. She noted that the “entire . . . causal chain of the suit” depends on the claim that the energy companies have “caused emissions to increase,” so “everything depends on . . . this idea that the defendants are responsible for excessive emissions.” But the Clean Air Act “sets up a scheme for deciding what are excessive emissions and what are not.” She asked Boulder’s attorney why the Court shouldn’t hold that Boulder’s suit “get[s] in the way of how Congress decided to regulate greenhouse gases.”
At bottom, the case is about whether Boulder can wield Colorado tort law to punish energy producers for harms purportedly attributable to lawful energy production occurring worldwide. Justice Gorsuch picked up on this thread in his questions to Boulder’s attorney, asking him whether there was “anything anomalous . . . to applying state law here to worldwide conduct.”
Justice Barrett raised a related hypothetical, asking Boulder’s counsel whether Colorado could pass a law capping emissions in the other 49 states. He conceded that such a law would be unconstitutional, but he resisted the suggestion that Boulder is barred from achieving the same ends through state tort litigation.
If Boulder’s claims are allowed to proceed, similar suits will proliferate. As Chief Justice Roberts put it to Boulder’s attorney, “Presumably, if you prevail, the next day, a municipality in every single state will file a lawsuit.” But the ensuing judicial chaos would not be limited to claims against energy producers. When Justice Thomas pressed Boulder’s attorney for a limiting principle, he conceded that nothing in his theory would limit Boulder from suing fuel retailers as well. As other commentators have noted, similar state tort suits against other major industries could follow, ranging from guns to plastics and beyond.
Fortunately, it appears from today’s argument that the Court is poised to shut down Boulder’s bid to regulate global emissions. A decision reaffirming that interstate air and water disputes must be governed by federal law would deal a crucial blow to the left’s climate lawfare and would reaffirm fundamental structural principles enshrined in our Constitution. In an era where blue states and municipalities are increasingly turning to litigation to achieve nationwide policy goals that would never survive in Congress, those principles are more important than ever for preserving our federalist system.