Document Type


Publication Date



Environmental Protection Agency, EPA, Supreme Court, climate change, Clean Air Act


In its first full Term with its newest member, the U.S. Supreme Court marched decidedly to the right with decisions narrowing abortion rights, striking down affirmative action programs, invalidating campaign finance regulations, and making it more difficult for victims of employment discrimination to seek redress. In the face of this rightward shift the most surprising decision of the Term was the Court’s embrace of claims that the U.S. Environmental Protection Agency (EPA) had acted unlawfully by refusing to use the Clean Air Act to combat climate change. In Massachusetts v EPA, the Court held that EPA had the authority to regulate emissions of greenhouse gases from motor vehicles under the Clean Air Act, and it ordered the agency to reconsider its refusal to do so. The Court’s decision vividly illustrates important features of its approach to regulatory issues today. The Court decided the case by a 5-4 margin, with Justices in the majority and dissent sharply disagreeing with each other on issues of constitutional law, statutory interpretation, and administrative law. As in each of the other twenty-three cases the Court decided by a single vote during this Term, Justice Kennedy cast the deciding vote. The ultimate lineup of the other eight Justices was entirely predictable. Justices Stevens, Souter, Ginsburg, and Breyer joined Kennedy in siding with the environmental plaintiffs, while Justices Scalia, Thomas, Chief Justice Roberts, and Justice Alito voted to uphold the agency’s refusal to act. At first glance Massachusetts v EPA may seem to be a surprising green turn by the Court (one scholar called it “as close as we will come” to a “Brown v. Board of Education for the environment”). Environmental advocates hope it will spawn regulatory action to combat climate change; some anticipate a new flood of lawsuits against major sources of greenhouse gas emissions. While the decision is a profoundly important victory for environmentalists, lurking beneath its surface is a harsh reality: the decision confirms that the Justices are even more sharply split over foundational principles of the regulatory state than they were before the addition of the Court’s two newest members. Four Justices highly skeptical of environmental regulation narrowly construe regulatory statues and seek to restrict citizen access to the courts to implement and enforce federal regulatory programs. Four other Justices are decidedly more sympathetic to the broad purposes of the environmental laws and the citizen suit provisions incorporated into them. Justice Kennedy is the man in the middle – skeptical of regulation, but open to accommodating the orderly evolution of the modern regulatory state. The struggle between these two camps echoes centuries-old tensions between the common law’s skepticism of regulatory interventions by government and the civil law’s greater tolerance for them. These tensions were most evident when U.S. courts heard early challenges to the New Deal’s regulatory programs. Despite the rise of the modern regulatory state, these tensions frequently resurface as courts review regulatory decisions by administrative agencies. After describing this emerging pattern, this article examines how it is reflected in the sharp divisions between the majority and dissenting opinions in Massachusetts v EPA. It then discusses the implications of this decision for the struggle to overcome barriers to global, collective action to respond to climate change.


Environmental Law