Since the start of the Trump administration, state and city governments have been expanding their role in environmental regulation. Last fall, the cities of Oakland and San Francisco joined the states of New York and Massachusetts in bringing lawsuits against oil companies for perceived harms related to global warming. On Friday, attorneys general from 15 states pushed back on the lawsuit by filing an amicus brief in support of dismissing the case on behalf of the oil companies, arguing that the cities’ lawsuit was an attempt to answer a political question in the courts and threatened to result in extraterritorial regulation of economic activity outside of California.

“In the name of the State of California, the cities of San Francisco and Oakland seek to harness the power and prestige of federal courts to remedy global climate change,” the attorneys general write.

The attorneys general of Indiana, Alabama, Arkansas, Colorado, Georgia, Kansas, Louisiana, Nebraska, Oklahoma, South Carolina, Texas, Utah, West Virginia, Wisconsin, and Wyoming all signed on to the brief. The inclusion of Colorado is particularly interesting since it comes the same week that the city of Boulder began its own lawsuit against Suncor and Exxon Mobil.

The Oakland and San Francisco cases are worrying to many observers, who see them as a blatant attempt to use a court case in one state to impose environmental regulations on the entire country. For years, environmentalists had used suits against the Environmental Protection Agency (EPA) to push for the regulation of greenhouse gases and other pollutants. When he took over as head of the EPA, Administrator Scott Pruitt specifically halted the practice, which he said undermined public participation and transparency.

In the current case, Oakland and San Francisco opted not to sue the EPA, but instead brought a suit against five oil companies alleging that the production and sale of fossil fuels contribute to global warming and constitute a “public nuisance.” According to the attorneys general, this argument is both legally and philosophically-flawed. At its heart, it rests on the idea that the federal common law governs environmental regulation. However, the attorneys general argue that a previous Supreme Court case established that the Clean Air Act and EPA regulations had supplanted the federal common law for this issue.

“But the questions of global climate change and its effects—and the proper balance of regulatory and commercial activity—are political questions not suited for resolution by any court,” the brief argues. “Indeed, such judicial resolution would trample Congress’s carefully-calibrated process of cooperative federalism where States work in tandem with EPA to administer the federal Clean Air Act.”

In particular, the attorneys general are concerned by the attempt to use local harms to force the creation of national regulation.

“One state should not (even through relators) have the power to seek a judicial remedy as means of implementing a national regulatory regime for environmental and energy production policy. Such a scheme is contrary to fundamental notions of horizontal federalism,” the attorneys general write.

“California cannot evade the application of the Commerce Clause by using common law rather than state statutory law to regulate commerce occurring outside its borders. The constitutional restrictions on California’s ability to regulate out-of-state commerce “reflect the Constitution’s special concern both with the maintenance of a national economic union unfettered by state- imposed limitations on interstate commerce…” they continued.

The brief was applauded by manufacturers, who are concerned that a victory for the cities in this case could leave states open to an endless string of litigation.

“This brief signed by 15 attorneys general from across the country is a significant step in defending manufacturers in America and discouraging further costly litigation,” said Lindsey de la Torre, executive director of the Manufacturers’ Accountability Project.

“With strong support from the attorneys general across the country, manufacturers look to spend less time in the courtroom fighting baseless lawsuits that enrich trial lawyers and more time working towards meaningful solutions,” she said.

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