The Case Before the Supreme Court

Boulder County and the City of Boulder, Colorado filed a lawsuit against Suncor Energy and ExxonMobil alleging public nuisance, private nuisance, trespass, unjust enrichment, and civil conspiracy — all under Colorado state law. The alleged injury: climate change caused by greenhouse gas emissions.

In May 2025, the Colorado Supreme Court ruled that federal law did NOT preempt these claims and let the lawsuit proceed. Suncor and ExxonMobil appealed. The U.S. Supreme Court granted certiorari and is expected to hear arguments in the fall of 2026, with a decision due before July 2027, according to the law firm Beveridge & Diamond.

This is the first time the Supreme Court will directly consider whether federal law bars state climate-damage lawsuits.

Why This Isn't Just About Boulder

There are dozens of similar lawsuits filed by state and local governments across the country. All of them operate on the same theory: sue energy companies in local courts for the global consequences of burning fossil fuels.

The NFIB — which represents small businesses — filed an amicus brief alongside the Washington Legal Foundation warning that if these suits survive, it opens the door to countless similar lawsuits. Every state, every county, every individual plaintiff could theoretically sue the fossil fuel industry for climate-related injuries under their own local laws. Beth Milito, Vice President and Executive Director of NFIB's Small Business Legal Center, said plainly: "Allowing these lawsuits to continue will set a precedent for every state and local government, or individual, to seek legal relief for greenhouse gas emissions."

If Boulder wins, that precedent becomes reality.

The Constitutional Problem

Two separate amicus briefs — one filed by the Manhattan Institute's Ilya Shapiro alongside the Frontier Institute and Independence Institute, another drafted by law professors Eugene Volokh and Erik Jaffe for the advocacy group Neutral Principles — lay out implications that extend far beyond climate policy.

First Amendment. According to Volokh and Jaffe's brief, excerpted at Reason's Volokh Conspiracy, Boulder's lawsuit doesn't just target emissions — it targets what energy companies said about climate change. The lawsuit tries to punish companies for their political advocacy, lobbying, and public speech on a contested scientific topic. Core political speech doesn't lose its protection because a plaintiff calls it "marketing."

Foreign Commerce Clause. The Constitution gives Congress — NOT the states — exclusive authority to regulate commerce with foreign nations. Boulder is trying to impose Colorado nuisance law on companies operating in international markets, affecting supply chains and trade relationships that span the globe. According to the Volokh-Jaffe brief, this violates Article I's delegation of foreign commerce power to Congress and conflicts with the Tenth Amendment.

Democratic accountability. Shapiro's brief raises a structural concern: if Boulder wins, Boulder County residents effectively shape national energy policy through their local courthouse. But voters outside Boulder County have no say in the officials making that determination. This reflects the constitutional concern about how policy decisions should be made in a federal system.

The Court Might Not Even Reach the Merits

According to Beveridge & Diamond's analysis, when the Court granted certiorari, it also directed the parties to brief whether it has statutory and Article III jurisdiction to hear the case at all. That's unusual and suggests the Supreme Court could dismiss on technical jurisdictional grounds without addressing the preemption question.

Boulder argued in its opposition to certiorari that the Colorado Supreme Court's ruling was a state-court decision on state-law claims, limiting federal review. If the Court agrees, it could dismiss without addressing preemption. That would leave the lawsuits alive — at least temporarily.

What's Changed Since Early Briefing

Shapiro's Manhattan Institute brief flags two significant developments that occurred after earlier rounds of briefing.

One: The Maryland Supreme Court looked at substantially similar climate tort claims and reached the opposite conclusion from Colorado's court. Different states, different outcomes. That's exactly the kind of conflicting, patchwork regulation the Commerce Clause was designed to prevent.

Two: The EPA under the current administration rescinded its 2009 endangerment finding for greenhouse gases under the Clean Air Act and repealed accompanying motor-vehicle greenhouse gas standards. That's a significant shift in the federal regulatory landscape that directly affects the preemption argument.

What Mainstream Coverage Is Getting Wrong

Most mainstream reporting frames this as "energy companies trying to escape accountability."

The real question is who decides national energy and climate policy. A county commission in Boulder, Colorado — population roughly 330,000 — or the United States Congress representing 330 million Americans? The answer to that question reflects a constitutional rather than a partisan concern.

The fact that the federal government itself filed an uninvited amicus brief supporting Supreme Court review — described by Beveridge & Diamond as "very unusual" — signals how seriously even the executive branch takes the structural problem at stake.

The Decision Ahead

If the Supreme Court sides with Boulder, hundreds of local governments will have a template to drag energy companies — and eventually any industry tied to emissions — into local courthouses under whatever tort theory their lawyers can construct. Energy prices, supply chains, and national infrastructure decisions would be made in state courts by local judges answering to local politics.

If the Court sides with Suncor and ExxonMobil, it draws a clear line: climate policy is a federal question. States cannot regulate international commerce and global atmospheric issues through nuisance law.

A decision is expected by July 2027.