of Atlanta -- Atlantic herring fishermen# should be required to pay for a cost monitoring system on their boats, or whether# that requirement is governmental overreach.

But, as William Brangham reports,# the outcome of this case could have## enormous impacts far beyond the fishing industry.

WILLIAM BRANGHAM: At issue here is# what's called the Chevron deference.## It's named after the oil and gas company# whose case created this legal prec It says, if there is a dispute over some ambiguous# regulation, the deference should go to the## government agency whose experts wrote the rule.# That's what those fishermen are arguing against,## and they're being supported by industry# groups who also want to curtail regulation.

If Chevron is knocked down, it could upend rules# governing nearly every slice of American society,## health care, environmental and workplace# protections, public education, banking, and more.

To understand what's at stake, we are# joined again by NPR's Carrie Johnson,## who was at the court for today's arguments.

Carrie, thank you so much for being back again.

Sticking with this fishermen's case,## can you explain what the arguments were i CARRIE JOHNSON, NPR: These plaintiffs are# a small group of fishermen based in the## Northeastern United States.

And a few years ago,# the Fisheries Service basically requiring them to have professional# observers or monitors on their boats, sometimes## on an overnight basis, to make sure they were# following the rules, and a decree that they should## have to pay for the monitors to the tune of about# $700 a day, which they say is just too much money.

They say it was never clear that# Congress intended for them to have## to pay.

And so they took this case# all the way to the Supreme Court,## arguing that the federal agency# here had overreached against them.

WILLIAM BRANGHAM: I see.

it might be onerous on the fishermen, but that's# the rule, and the agency gets to determine that.

CARRIE JOHNSON: That's right.

In this case, the lower courts ma ndate under the law that these fishermen# would have to pay.

They firmly resisted that## and took this case all the way up to the# Supreme Court, where it ended up today.

WILLIAM BRANGHAM: So you can see why# business interests don't like this## idea of some agency basically winning every# toss-up ball over a fight over Wh at is their broader argument# about this deference principle?

CARRIE JOHNSON: Ultimately, they say that# this is a matter of the executive branch## of the government, unelected federal# bureaucrats, taking power that should## belong to the United States Congress# and, to some extent, to federal judges,## who all along have interpreted the law# and who can interpret these laws and## these regulations just fine on their own# without any input from federal agencies.

And they say that, for many years now, almost 40# of them since this case was decided back in 1984,## it's really upended the balance# of power between the branches,## and it's put a lot of onus on small businesses# like these fishermen and oth themselves against federal agencies,# when they have a hard time winning there.

This case was supported not just by these# small fishing industries, but a number of## very large conservative legal foundations,# groups like the Gun Owners of America,## a trade group for e-cigarette manufacturers and# others, just showing how sweeping this case could## be if the Supreme Court ultimately decides to# overrule that precedent from all those years ago.

WILLIAM BRANGHAM: Let's talk# a little bit about that,## because the opponent consumer protection groups, and others like that,# argue that this would, in essence, sow chaos.

What is their argument?

Why do# they say Chevron should stay?

CARRIE JOHNSON: They basically argue# that there's a hidden agenda in this## case beyond the herring fishermen, who are# the plaint to paralyze or cripple the bureaucracy, so# that federal agencies cannot make rules on## major problems in American life, things# from air pollution and maybe eventually## even artificial intelligence, as Justice# Elena Kagan raised today, to health care.

And they say, if you return these decisions# to the hands of unelected federal judges,## there's something like 800 of them# around the country, it risks people's## Medicare and Medicaid programs, very complex# programs that mean a lot to people's lives,## being decided one way in one state and one# way -- in another way in another state.

And that could really sow chaos for people's lives# just in their personal pocketbooks, as well as## for environmental regulations and workplace# protections.

You just can't have a system## where the regs mean something in one state and# mean something else halfway around the country.

WILLIAM BRANGHAM: I know that,# in his confirmation hearings,## now-Justice Gorsuch expressed a great# deal of skepticism, and I know ot her conservative justices similarly# have shown some antipathy to regulation.

From your reading of the arguments today,# what is your sense?

Do you think the majority,## the conservative majority,# is going to strike it down?

CARRIE JOHNSON: We did hear# deep skepticism from justice## Neil Gorsuch today.

He raised a lot# of very, very tough qu solicitor general.

And Justice Brett# Kavanaugh was also pretty skeptical,## Justice Sam Alito along the same lines.

And# Clarence Thomas asked a few questions too.

But those, William, are four votes, and I didn't# hear a clear fifth vote for getting rid of this## precedent altogether.

In fact, one of the Trump# appointees, Justice Amy Coney Barrett, raised the## specter of getting rid of this precedent might# mean inviting floodgates of litigation from## thousands of litigants who have had their cases# decided based on this principle over many years,## and that really swamping the courts and# potentially the Justice Department too.

So it's not clear to me there are five votes# to overturn this precedent altogether.

It may be that the court compromises and chips# away further at the precedent, though.

WILLIAM BRANGHAM: All right, Carrie# Johnson of NPR, thank you, as always.

CARRIE JOHNSON: My pleasure.