(NewsNation) — The U.S. Supreme Court will hear a case that could eliminate a fee requirement for commercial fishermen, an important case that could limit a wide swath of government regulations.

In cases being argued Wednesday, lawyers for the fishermen are asking the court to overturn a 40-year-old decision that is among the most frequently cited high court cases in support of regulatory power.

Lower courts used the decision to uphold a 2020 National Marine Fisheries Service rule that herring fishermen pay for monitors who track their fish intake. A group of commercial fishermen appealed the decision to the Supreme Court.

Business and conservative interest groups who want to limit federal regulators think they have a winner in the Atlantic herring and the boats that sweep the modest fish into their holds by the millions.

Jody Freeman, a law professor at Harvard University, joined “NewsNation Now” to discuss the case, saying the argument is about power, not fish.

“On the surface, it’s a case about fisheries regulation. But underneath, it is the big question. And that’s whether administrative agencies that regulate our food and drug supply and financial institutions and public health and safety — whether they can have some latitude when they interpret and enforce federal law. It’s about whether they get to decide how to fill ambiguities and gaps in the laws they implement,” Freeman said.

“The case is about power. It’s not really about fish. And it looks like the Supreme Court might come out of this is the most powerful policymaking institution in America,” Freeman told NewsNation.

Billions of dollars are potentially at stake in front of a court that, like the rest of the federal judiciary, was remade during Trump’s presidency by conservative interests.

Supporters of limited government have had their sights set on the decision for years, which they say gives power that judges should wield to experts who work for the government.

The 1984 decision in the case, known colloquially as “Chevron,” states that federal agencies should be allowed to fill in the details when laws aren’t crystal clear.

“So if the fishermen win, and they get everything they want, the Supreme Court will essentially be saying federal agencies do not have the power to read into the ambiguities and laws,” Freeman said.

“It’s going to be up to the court to determine all of the interpretive questions that come up when you regulate all the things that federal agencies regulate,” she explained.

Gun, e-cigarette, farm, timber and home-building groups are among the business groups supporting the fishermen. Conservative interests that also intervened in recent high court cases limiting regulation of air and water pollution are backing the fishermen as well.