Boulder, Colorado sued Exxon Mobil and Suncor Energy in state court in 2018. The city and county want money for climate damage, including wildfire costs. The companies say federal law blocks the suit, and the Trump administration agrees. The Supreme Court heard nearly two hours of argument on Monday, October 5. Justice Samuel Alito recused himself on September 28 and gave no reason, so only eight justices heard it. If the eight justices tie 4-4, Colorado's ruling stands and the Court sets no national rule. The Court should rule by summer 2027. Dozens of similar suits are pending.

Only Federal Law Can Govern Climate Harm

Exxon, Suncor and the Trump administration say one state's courts can't put a price on global emissions.

A Colorado jury shouldn't set climate policy for the world. Kannon Shanmugam, the lawyer for Suncor and Exxon, called Boulder's suit an "unprecedented effort to use state law to regulate global conduct." He warned it could invite suits from roughly 90,000 municipalities. Sarah Harris, the principal deputy solicitor general, spoke for the Trump administration. She said the theory "egregiously exceeds constitutional limits on state authority." Sai Prakash, a University of Virginia law professor, warned the liability "can attach" to "thousands of others as well."

Several justices asked questions that matched the companies' argument. Justice Brett Kavanaugh pointed to "a wall of precedent" that treats interstate pollution as a federal matter. Chief Justice John Roberts asked whether a Boulder win would mean a municipality in every state files suit the next day.

States Have Always Let People Sue for Harm at Home

Boulder says its suit targets deception, and states have long let people sue over injuries inside their borders.

Boulder is suing over what the companies told the public. Kevin Russell, Boulder's lawyer, said states have always had the power to provide tort remedies for injuries inside their borders. He said the suit concerns deception and producers, not emissions. Justice Sonia Sotomayor noted the Clean Air Act doesn't regulate fuel marketing. The Court took the case in February. Boulder Mayor Aaron Brockett said then that it should affirm Colorado's right to hold these companies accountable.

Tobacco and opioid cases are the model. Justice Elena Kagan called Boulder's suit "chapter 3" after the tobacco and opioid cases. She asked whether chapters 1 and 2 were also preempted. She also asked the companies where the text supports their constitutional argument. Earthjustice filed a brief for Boulder and makes the same comparison. Justice Neil Gorsuch also sounded unconvinced by the companies' preemption claims. Roberts pressed both sides, noting that people can often sue in their home state over conduct with effects in many states.

The Court May Be Deciding This Too Early

Some justices asked why the Court is stepping in before Colorado has held a trial.

The case may not be ready for the Supreme Court. Justice Ketanji Brown Jackson called the review "premature" and asked why the Court shouldn't wait for Colorado's courts to finish. Sotomayor also questioned whether the Court has jurisdiction yet. Justice Clarence Thomas also asked mostly about jurisdiction. Boulder itself argued the Court should wait.

The justices in the middle haven't picked a side. Justice Amy Coney Barrett called the companies' constitutional argument "a little slippery." She also said, "Everybody agrees that state tort law is a form of regulation." UCLA law professor Alejandro Camacho said she seemed open to a narrower ruling that favors the companies. Court-watchers saw only Kavanaugh fully backing the companies' theory. They saw no shared theory among the other justices.

Where This Lands

The companies and the Trump administration say climate harm is a federal matter and one state can't price it. Boulder says states can hear a deception claim like any other tort suit. Some justices think the Court should wait for Colorado's trial first. On Monday, no single legal theory won a majority of the justices.

Sources