A Response to Michael Buschbacher on Suncor Energy v. Boulder County

I appreciate my friend Michael Buschbacher taking the time to respond to my amicus brief in Suncor Energy v. Boulder County and my other work in this space. That he and others believe my work is worth responding to suggests that he and others believe it is important. (As they say, if you are taking fire, you must be over the target.) Yet he is mistaken to think that my arguments–-let alone the relevant history or legal principles–support the petitioners in this case.

To understand our disagreement, it is important to understand what is and what is not at issue in Suncor. The question is not whether the plaintiffs here (or in other climate cases) are making bold, ambitious, or potentially overbroad claims. Nor is it whether the alleged chain of causation is too attenuated and the attempt to attribute harms in Colorado to emissions elsewhere too speculative to support liability. Nor is it whether there are grounds to narrow or pare down the scope of the conduct they challenge or damages they seek. Rather, the question is whether the plaintiffs are wholly precluded from making their claims under state law, such that the case must be dismissed. After all, the Suncor petitioners are asking the Supreme Court for only one thing: An order reversing “the Colorado Supreme Court’s decision to allow Boulder’s claims to proceed.” That request should be denied, which is why I filed a brief in support of the respondents.

As framed by Mr. Buschbacher, “the central question in Suncor is whether states and municipalities can apply their own law to regulate the greenhouse-gas emissions of fuel producers and users.” This is not quite right. The plaintiffs’ claims do not target emissions, as such. Rather, their claim is that the production and marketing of fossil fuels by the defendants as caused or contributed to harms in Colorado, and Boulder County seeks compensation for such harms. 

In considering the plaintiffs’ claims, it is worth remembering that state tort law is routinely applied to conduct that occurs outside of the given state’s borders. Consider routine product-liability claims. The law of the jurisdiction in which the harm occurred is often applied to companies that manufactured, sold, or marketed allegedly defective products elsewhere. And, provided the requirements of personal jurisdiction have been satisfied, this presents no constitutional problem. Such claims must be properly constrained, but they are not precluded.

Under current law, the federal government has the authority to preempt plaintiffs claims should it want to do so, but it hasn’t. Nor has the federal government ever enacted any statute governing the conduct targeted by the plaintiffs’ claims. This likely explains why, as the litigation has gone on, the petitioners have de-emphasized their statutory arguments in favor of the broad–and untenable–claim that the constitution wholly precludes any state law claim against conduct that produces harm across state lines or international boundaries. 

Mr. Buschbacher notes my concern about “home cooking”– and this is a legitimate concern. There are limits to the extent to which states may impose the consequences of their policy choices on their neighbors. It is one thing for state courts to hear tort claims seeking recompense for damages born within their jurisdiction due to out-of-state conduct. It is quite another for state courts to impose punitive damages or demand compliance with local standards in far off places. This is the boundary the Court has already drawn in limiting the imposition of punitive damages for what is lawful out-of-state conduct. But the concern for state prerogatives cuts both ways. If Colorado may not impose its policy judgments upon conduct occurring elsewhere, then neither may other States impose upon Colorado the costs of the conduct they license. As with punitive damages, concerns about legitimate state authority may well counsel narrowing Boulder County’s claims–as my brief concedes–but they do not justify preempting them. 

Mr. Buschbacher raises International Paper v. Ouellette, but fails to heed its lesson.In Ouellette, a majority of the Court concluded that, due to the federal Clean Water Act, Vermont plaintiffs could not sue a New York paper mill under Vermont law because doing so would subject the facility to potentially conflicting legal standards, only one of which had been blessed by the federal government. The mill in Ouellette was subject to regulation as a “point source” under the CWA, and (owing to the CWA’s cooperative federalism structure) this regulation was carried out by New York authorities under New York law. Accordingly, the decision as to how much the mill could discharge in waters of the United States was, for purposes of federal law, a matter of New York law–and to this Vermont law had to yield.

The Court in Ouellette made this point explicit, noting that “if affected States were allowed to impose separate discharge standards on a single point source, the inevitable result would be a serious interference with the achievement of the ‘full purposes and objectives of Congress.'” Yet insofar as state-law claims do not threaten to impose “separate . . . standards on a single point source” there is no conflict and no basis for preemption. And here, as Mr. Buschbacher knows, Boulder’s claims do not target conduct–let alone emissions–that are subject to regulation under federal law. 

While barring the application of Vermont law to an out-of-state point source subject to the CWA’s regulatory scheme, Ouellette expressly preserved the ability of plaintiffs to pursue state law claims against the out-of-state mill–and the justices were unanimous on this point. As the Court submmarized its own holding:

Nothing in the Act prevents a court sitting in an affected State from hearing a common law nuisance suit, provided that jurisdiction otherwise is proper. Both the District Court and the Court of Appeals erred, however, in concluding that Vermont law governs this litigation. The application of affected-state laws would be incompatible with the Act’s delegation of authority and its comprehensive regulation of water pollution. The Act preempts state law to the extent that the state law is applied to an out-of-state point source. [Emphasis added.]

Mr. Buschbacher suggests that the plaintiff’s invocation of Colorado law in their complaint should nonetheless be fatal to their claim. Again, reference to Ouellette is instructive. There, as here, the plaintiffs filed suit under their home state’s law. And yet, after concluding that Vermont plaintiffs could not sue a New York point source regulated as such under the CWA under Vermont law, it did not order dismissal of the case. Rather, the case was remanded to the lower courts where appropriate state law was applied as the litigation proceeded. Further efforts to bar the suit were rejected and International Paper ultimately offered substantial settlement. So even if one were to conclude that Boulder County can do no more than seek to apply home-state law to each of the defendants’ operations (something I do not believe current law requires), the petitioners’ plea to reverse the Colorado Supreme Court and dismiss the case must be rejected.  

According to Mr. Buschbacher, “Boulder County’s suit is almost entirely about conduct far outside of Colorado” (emphasis added). I think this framing settles the question. Even were I to concede ever point Mr. Buschbacher makes, it would not justify dismissing the case, for insofar as Boulder County’s suit includes petitioners’ conduct that occurred in Colorado, it must be allowed to proceed, at least with regard to such conduct. I believe that current law allows for more; Mr. Buschbacher disagrees. But this is a dispute about the permissible scope of this litigation, not whether it should be allowed to continue. It is the latter question the petitioners have put before the Court, and that is the question my brief addresses.

For more on the case, here are (some of) my posts on the subject (with more to come):

• Climate Change Goes Back to the Supreme Court — Colorado Edition, Feb. 23, 2026.
• Previewing Suncor Energy v. Boulder County, Mar. 6, 2026.
• Amicus Brief in Suncor Energy v. County Commissioners of Boulder County, Aug. 3, 2026.
• Supreme Court Term to Start Hot, Aug. 6, 2026.
• As Suncor Approaches, Justice Alito Recuses, Sept. 28, 2026.
• Buschbacher: Did Prof. Adler File His Amicus Brief for the Wrong Side in Suncor?, Oct. 1, 2026.
• Unpacking the Suncor Oral Argument: Two Upcoming Events, Oct. 5, 2026.