This post was updated Aug. 4 at 10:11 p.m.

The U.S. Supreme Court ruled in a 6-3 decision June 28 to overturn the Chevron doctrine.

The Chevron doctrine – named after the 1984 Supreme Court case Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc. – is a judicial ruling that states how courts should evaluate the legal standing of federal agency actions, said Cara Horowitz, executive director of the Andrew Sabin Family Foundation of the Emmett Institute on Climate Change and the Environment at UCLA School of Law.

The law stated that courts must defer to a regulatory agency’s interpretation of a federal law if said legislation is ambiguous. In the past, when federal agencies executed legislation passed by Congress – such as the Environmental Protection Agency implementing the Clean Air Act – they often could interpret these statutes themselves, Horowitz said.

She added that the doctrine may be thought of as having two steps.

The first step of the doctrine asks if Congress was clear in its law, Horowitz said. She added that the second step is that if it is deemed that Congress was ambiguous in what the law allows the agency to do, a court will defer to the agency’s interpretation – even if that interpretation is different than its own.

Horowitz said determining Congress’ intent can sometimes be difficult.

“Often, Congress is an imperfect drafter … because Congress is rushing or because Congress isn’t an expert in the matter or because political compromises require a degree of vagueness to pass statutes … or just because Congress didn’t have in mind the particular circumstances that later arose,” she said. “Congressional statutes might be ambiguous about what an agency’s authority is.”

With the overturning of the Chevron doctrine, the Supreme Court changed the weight courts give to administrative agencies, said Julia Stein, deputy director for the Emmett Institute on Climate Change and the Environment at UCLA School of Law.

This ruling will consolidate more power in the hands of the judiciary, Stein said. She added that Congress is unlikely to amend these laws for clarity, thus leaving the interpretation of ambiguous legislation to the courts.

“If you take the field that I practice with, environmental law, in many cases the statutes that we’re working under are decades and decades old and have not been significantly amended in decades,” Stein said. “The Supreme Court or lower courts might say something about those laws, but Congress is not going to at this juncture because of the political dysfunction in Congress. It’s not acting to amend those statutes to make them more clear.”

Stein added that she believes this shift in power to the judiciary is problematic for several reasons, including that administrative agencies are operated by those who have scientific and technical expertise and experience that courts do not have.

Another reason is that judges are not democratically accountable to the people, Stein said. Supreme Court judges are appointed for life, and if they make a decision interpreting a law that most Americans disagree with, they face no threat to their position, she added.

In contrast, the leaders of federal agencies change and are directed by a democratically-elected administration, Stein said.

“The kinds of regulations the Trump EPA (Environmental Protection Agency) was producing are really different from the ones the Biden EPA is producing, even though that agency has, the whole time, been populated by bureaucrats with technical expertise,” Stein said. “There’s a much higher level of democratic accountability for administrative agencies than there is for the judiciary.”

The increase in power of the federal courts is likely to empower lawyers over scientists, said Blake Emerson, a professor of law and political science at UCLA.

“There are some issues about what law means that aren’t really questions about the things we learn in law school – not about the best way to interpret texts or about how to reason by analogy from cases,” Emerson said. “Instead, they’re really about scientific knowledge as well as about political considerations about what’s best for the country, and those are not tools that lawyers are trained in.”

This change in power may also hinder the federal government in addressing public risks, Emerson said.

“The Chevron doctrine has played an important role in enabling the federal government and the executive branch, in particular, to issue policies and make regulations that are well-considered and that are likely to address serious risks to public health and safety,” Emerson said. “I worry that without the Chevron doctrine, the government will have less capacity to do that.”