Chevron deference solves emissions.

Environmental regulation is the final area in which an activist conservative Court could have a substantial effect. The source of the Court’s power here lies in the relationship between environmental legislation and regulation. In general, Congress has chosen to deal with the environment by passing very general laws and delegating the authority to implement them to regulatory agencies like the Environmental Protection Agency.

An activist conservative Court could make life difficult for a Democratic EPA by blocking regulation directly, declaring it “arbitrary and capricious” under the Administrative Procedure Act. The courts are only supposed to use this tool to block actions that are genuinely irrational or that exceed the agency’s legal authority; but the Court could deploy it much more aggressively than has been done in the past.

In practice, environmentalists could try to get around such a judicial barrier by lobbying Congress to pass laws directing that a specific regulation be adopted, rather than delegating so much authority to the EPA. If public opinion were strongly enough in favor of increased environmental protection, a Democratic Congress and president could probably get some regulation adopted despite judicial resistance.

A conservative Court could also impede environmental reform by second-guessing agencies’ interpretations of federal law. According to what is known as the “Chevron doctrine,” when federal law is ambiguous, the Court will defer to an agency’s interpretation of the law provided it is reasonable. This doctrine is intended to give substantial power to agencies, binding the hands of judges who might otherwise disagree with the agencies’ policies.

Today Chevron is under attack, most prominently from Gorsuch, who has written disparagingly of the idea that courts would have anything less than full control over the meaning of federal statutes. This is bad news for environmental regulation—and that is almost certainly part of the point. A Court that does not defer to an agency’s interpretation of federal law can substitute its own policy judgment for that of the agency. If that agency is the EPA, and its judgment is being used to expand environmental protection, then a conservative Court that overturned Chevron or weakened its rule of deference would stand ready to reverse the agency’s course.