Lawyers and Supreme Court commentators hardly seem the type to camp out for tickets. But that’s precisely what a line of expectant court-watchers will be doing one week from today — braving early morning Capitol Hill in hopes of gaining entrance to oral argument in Massachusetts v. EPA.

Like a pre-game sportscast, today’s post will attempt to give a flavor for points of contention — in this case, the legal issues before the court. It won’t be exhaustive. If you’re looking for greater detail, refer to either the briefs or to this recent report (PDF).

The case involves a suit by Massachusetts and its allies (a coalition of other states and nonprofit groups) — I’ll refer to them as the petitioners — against the EPA for refusing to use the Clean Air Act to regulate greenhouse gases, including carbon dioxide emitted from motor vehicles. The petitioners lost (PDF) in the U.S. Court of Appeals for the D.C. Circuit, but convinced the U.S. Supreme Court to review the case.

When the Supreme Court decides to hear a case, it grants certiorari on specific questions. In Massachusetts v. EPA, the Court agreed to consider two:

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  • “Whether the EPA Administrator has authority to regulate carbon dioxide and other air pollutants associated with climate change under [the Clean Air Act]” (I’ll call this the authority issue), and
  • “whether the EPA Administrator may decline to issue emission standards for motor vehicles based on policy considerations not enumerated in [the Clean Air Act]” (I’ll call this the discretion issue).

There’s also the potential for a sleeper issue: Constitutional standing. Over the years, the Supreme Court has crafted an elaborate body of law that governs whether a suit involves, in the words of Article III of the Constitution, a “case or controversy.”

To have “standing,” a litigant must show that she has suffered a particularized injury, the injury is caused by the defendant’s actions, and the court has the ability to redress the injury. All courts must ensure that litigants have standing before adjudicating a case.


Petitioners argue that the clear language of the Clean Air Act provides the EPA with authority to regulate greenhouse-gas emissions from motor vehicles. The Act authorizes regulation of “air pollutants,” which are defined, in complicated fashion, as including “any air pollution agent … including any … chemical … substance … which is emitted into … the ambient air.” (The full definition is 43 words long, but those are the relevant ones.)

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EPA argues that when Congress enacted the Clean Air Act, it said nothing about addressing global warming. Therefore, the agency does not believe carbon dioxide (and other greenhouse gases) should be considered an “air pollution agent.”


Petitioners argue that if EPA has regulatory authority, the statute identifies all of the criteria EPA may consider in deciding whether to act. The Clean Air Act states that EPA “shall” regulate air pollutants that, in the agency’s judgment, “cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare.”

In petitioners’ view, the agency only has the discretion to determine whether an air pollutant is likely to endanger public health or welfare. The statute doesn’t permit consideration of anything else.

EPA argues that it has inherent discretion to decline to conduct the initial analysis. In other words, EPA believes it can refuse to determine, for any reason it sees fit, whether greenhouse gases endanger public health or welfare. In this case, the agency says it does not believe the Clean Air Act is the best way to address global warming, and therefore it decided not to conduct such an analysis.


EPA argues that petitioners do not have standing because the amount of greenhouse gas the agency could conceivably eliminate is too small to have an appreciable impact on global warming. Thus, the court cannot issue an order that will protect petitioners.

While EPA does not press this argument, one judge on the D.C. Circuit believed petitioners lacked standing because global warming causes a “global” injury that, in the judge’s view, does not support a lawsuit.

Petitioners disagree. They argue that regulating cars and trucks is an important step in establishing a sustainable carbon policy to address global warming. Further, they identify numerous ways that global warming will cause unique injuries. In Massachusetts, for instance, sea level rise associated with global warming may endanger the state’s beautiful and heavily visited beaches.

Looking Ahead

Oral argument is scheduled to begin at 10:00 AM on November 29th. For the fanatical (like me), a transcript of the argument should be available that afternoon. The Georgetown Environmental Law & Policy Institute will also be hosting a discussion of the oral argument at 12:15. You can watch a live webcast of the event here.