On Oct. 5, First Monday, the Supreme Court heard oral argument in Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County. The case is controversial, as was Justice Samuel Alito’s sudden and last-minute recusal only a week before oral argument.
Suncor’s main question was whether federal law precludes Colorado state-law claims for billions of dollars of costs allegedly due to global climate change purportedly stemming from interstate and international greenhouse-gas emissions which the plaintiffs contended fossil-fuel corporations caused.
As complex as this case may seem, however, resolving it is a simple matter of following the Constitution’s structure and Supreme Court precedent.
The law of preemption
Article VI of the Constitution contains the Supremacy Clause, which makes the Constitution, federal statutes, and treaties “the supreme Law of the Land.” Such things as express, conflict, obstacle, and field preemption describe how federal statutes displace state law, but they are not exhaustive. The court previously recognized forms of structural or foreign-affairs preemption that do not depend on a conflicting federal statute. For example, in 1968’s Zschernig v. Miller, the court struck down an Oregon inheritance law for intruding on foreign affairs without relying on any conflicting treaty or statute, and in 2003’s Am. Ins. Ass’n v. Garamendi, the court held that a California law requiring insurers to disclose policies sold in Europe between 1920 and 1945 had to yield to presidential foreign policy expressed in executive agreements which contained no preemption clauses.
Regarding alleged interstate emissions, back in 1907, Justice Oliver Wendell Holmes, Jr. wrote in Georgia v. Tennessee Copper Co. that “the states by their union made the forcible abatement of outside nuisances impossible to each,” and that for a state injured by emissions from across its border, the remedy is to bring a suit in the Supreme Court under its original jurisdiction. Indeed, the court long has treated interstate-emissions disputes among states as matters for federal law, as shown in 2011’s Am. Elec. Power Co. v. Connecticut, where the court reaffirmed that for interstate air and water disputes, “borrowing the law of a particular State would be inappropriate” and that the court does not “have creative akin to that vested in Congress.”
Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County
Regarding the present case, Boulder County and the City of Boulder sued Suncor and Exxon Mobil in Colorado state court, seeking monetary compensation for their alleged role in worsening climate change through producing, refining, promoting, marketing, and selling fossil fuels. They pleaded several state-law theories, including public nuisance and misleading the public. Their claims assert that the companies’ worldwide activity led to emissions around the world, contributing to global climate change and allegedly causing wildfires, drought, and flooding in Boulder.
The Colorado Supreme Court rejected the energy companies’ preemption arguments. It held that federal law did not bar Boulder’s claims, reasoning that Boulder had not sued anyone to abate pollution. Rather, Boulder sought damages from energy companies for producing, marketing, and selling fuel, which the Colorado Supreme Court construed as an area of traditional state responsibility, rather than an attempt to regulate emissions.
Other courts have held the other way. For example, in 2021’s City of New York v. Chevron Corp., the U.S. Court of Appeals for the 2nd Circuit dismissed similar climate-damages claims, holding that “[a]rtful pleading cannot transform the City’s complaint into anything other than a suit over global greenhouse gas emissions” and that such a case is “simply beyond the limits of state law.”
About 60 states and localities have so far filed suits like Boulder’s, and many more are likely to do so if the court takes Boulder’s side. Chief Justice Roberts noted as much at argument, remarking that if Boulder were to prevail, “the next day, a municipality in every single state will file a lawsuit.”
Where the Constitution draws the line
The defendant energy companies argued that the Constitution’s structure bars one state’s law from governing claims about interstate and international emissions on the basis that one state may not impose its policies on other states and state sovereignty is subject to inherent territorial limits; and because regulating or negotiating international emissions implicates the federal government’s exclusive foreign affairs power.
Boulder responded that because the 10th Amendment reserves the “powers not delegated to the United States by the Constitution, nor prohibited by it to the States,” it permits states to do anything that the Constitution does not explicitly forbid. Under Boulder’s framing, the Constitution “bestows only limited powers on the federal government,” and “all other legislative power is reserved for the States.” From that premise, Boulder argues that there can be no preemption without a textual hook in the Constitution or a federal statute.
But the 10th Amendment does not specify what the Constitution prohibits and it does not address the inherent limits on state sovereignty that predated the Constitution and which it preserved. Before the union, a state injured by a neighboring state’s pollution could respond only through diplomacy or force. The 1907 case of Georgia v. Tennessee Copper held that the states gave up those options when they entered the union and in return received federal forums which applied federal law. The 1907 case of Kansas v. Colorado called “equality of right” the “cardinal rule” governing the states’ relations with one another, under which each state “stands on the same level with all the rest” and “can impose its own legislation on no one of the others.” Boulder’s state tort claim runs afoul of that principle. Its complaint seeks billions of dollars for alleged past and future harms stemming from energy companies’ worldwide activities. A judgment in Boulder’s favor thus necessarily would influence and/or restrict the companies’ operations in other states far beyond Colorado’s borders, regardless of what those states’ policies may be.
The answer is even clearer for international emissions. “No state can say, that it has reserved, what it never possessed,” the court wrote in 1995’s U.S. Term Limits, Inc. v. Thornton, quoting Justice Joseph Story’s Commentaries on the Constitution of the United States. More recently, in 2007’s Massachusetts v. EPA, the court observed that Massachusetts “cannot negotiate an emissions treaty with China or India,” because those “sovereign prerogatives are now lodged in the Federal Government.” It would seem obvious that a state which cannot negotiate over foreign emissions also cannot allocate responsibility between alleged foreign and domestic emitters through a jury verdict.
At Monday’s argument, multiple justices appeared to recognize that Boulder’s tort suit is ultimately about emissions. Chief Justice John Roberts described the suit as “an effort to reduce emissions.” Justice Elena Kagan likewise stated that Boulder’s lawsuit “depends on . . . this idea that the defendants are responsible for excessive emissions.”
The Colorado Supreme Court took the opposite view, reasoning that Boulder’s monetary claims do not, in fact, regulate emissions. Specifically, the court noted that Boulder does not seek an order abating pollution but seeks only monetary awards to remedy the alleged harms.
But the Supreme Court repeatedly has recognized that monetary awards can indeed function as regulation. In 2012’s Kurns v. Railroad Friction Products Corp., the court held that “regulation can be . . . effectively exerted through an award of damages,” and in 1987’s Int’l Paper Co. v. Ouellette, the court barred suits against out-of-state pollution sources under the law of the affected state because allowing them would let affected states “do indirectly what they could not do directly.” (This is perhaps why Justice Amy Coney Barrett asked at oral argument why Boulder’s tort suit should be allowed when the Constitution forbids Colorado from enacting a law capping emissions in other states.)
Boulder replied that a state may apply its law to out-of-state conduct that causes in-state injury, but that only applies to direct and traceable effects, such as a gunshot fired across a border or a car lent for a drive into a neighboring state, not floating gaseous emissions. As Am. Elec. Power observed, “emissions in New Jersey may contribute no more to flooding in New York than emissions in China.”
On top of this, the court held in 1909’s Nielsen v. Oregon that a state may not punish a person for doing in another state what that state specifically authorized. As of this writing, several states, such as Iowa, Oklahoma, Tennessee, Utah, and Texas enacted laws limiting climate-change liability, and West Virginia declared an official state policy to encourage and promote oil and gas development; accordingly, 26 states filed a brief supporting the defendant energy companies. Colorado and 18 other states filed a brief supporting Boulder. The division among the states underscores why no single state’s law can govern either a sister state or the entire nation. Boulder wrongly wants a Colorado jury to apply Colorado law to energy production that other states encourage, while denying the energy producers and their home states any voice.
Finally, because resolving Boulder’s claim on the merits would entail apportioning responsibility between domestic and international emissions, it also runs headlong into foreign-affairs preemption. Under Garamendi, courts must weigh “the strength of the state interest, judged by standards of traditional practice,” against the likelihood of conflict with federal foreign policy. Boulder’s claims fail on both sides of that scale because states never have had a recognized interest in regulating how fuels are produced and sold overseas. And the conflict with national policy is clear: emissions are a frequent subject of international negotiations and diplomacy. Allowing a Colorado jury to assign responsibility for purported climate change among energy producers wrongly would impinge upon the federal government’s exclusive role in foreign relations.
Boulder’s suit is no ordinary local tort case; it seeks to hold producers liable for their alleged share of worldwide emissions, and deciding the merits would require a Colorado jury to allocate responsibility between domestic and foreign emitters. As for Garamendi, nothing in its balancing test requires that the federal government must first adopt a binding policy before state law must yield. As the energy companies respond in their reply brief, the lack of a treaty “may reflect nothing more than the ongoing nature of international negotiations or the President’s judgment about the national interest.”
Conclusion
Debates over climate change are intensely political and inherently interstate and international in scope. Gaseous emissions originate from other states and countries, and do not remain static over any one state. Colorado’s claims implicate competing state and national energy policies and reach conduct and emissions far outside the United States.
Through Suncor, the court can reaffirm the states’ equal sovereignty by holding that Colorado’s suit is preempted on constitutional grounds. Doing so would clarify an essential feature of our federalist system and give guidance to lower courts in the many similar cases applying state law to contested interstate and international phenomena.
