GEOFF BENNETT: Another big day at the U.S. Supreme Court, as the justices handed down a decision with major implications for firearm regulations.

In a 6-3 ruling, the conservative majority found that the government exceeded its authority when it issued a ban in 2018 on bump stocks.

That's a gun accessory used in the deadliest mass shooting in U.S. history.

AMNA NAWAZ: A bump stock is used on the back end of a semiautomatic rifle.

It allows the user to reengage the trigger continuously, dramatically increasing the rate of fire like that of an automatic weapon.

Marcia Coyle, our Supreme Court analyst, has been following this case closely and joins me now.

Marcia, it's always great to speak with you.

So, this federal bump stock ban was approved back in 2018 by then-President Trump, and it was in response to that 2017 Las Vegas outdoor music concert shooting; 58 people were killed.

A bump stock was used in that.

But just remind us, how did this issue get before the Supreme Court in the first place?

MARCIA COYLE, "The National Law Journal": The way so many cases do, Amna.

Michael Cargill, who was a gun shop owner in Austin, Texas, filed a lawsuit challenging the Bureau of ATF's rule, ban on bump stocks.

He won before the U.S. Court of Appeals for the Fifth Circuit.

It was the Biden administration that brought the case, the appeal to the Supreme Court.

AMNA NAWAZ: And, Marcia, this was not about the Second Amendment here.

This was about regulation and how the court views this -- views it.

Alito, writing in his concurring opinion, said this: "There can be little doubt that the Congress that enacted this law would not have seen any material difference between a machine gun and a semiautomatic rifle equipped with a bump stock.

But the statutory text is clear and we must follow it."

In her dissent, Justice Sotomayor said this: "The court puts bump stocks back in civilian hands.

To do so, it casts aside Congress' definition of machine gun and seizes upon one that is inconsistent with the ordinary meaning of the statutory text.

When I see a bird that walks like a duck, swims like a duck, and quacks like a duck, I call that bird a duck."

Marcia, what does this tell us about how the justices were thinking about this issue?

MARCIA COYLE: Well, first of all, this was very much a case of statutory interpretation, looking at the language of the statute.

And it tells us almost immediately in the vote that the justices looked at the language and saw it very differently on the left and the right.

In fact, Justice Kagan said at one point during arguments that, yes, textualism, sticking to the text is fine, but it's not inconsistent with common sense.

So she believed the court should be looking little broadly in terms of what the statute was designed to do.

But you can look at it two ways really, Amna.

It is of a piece with the conservative rulings in the recent years in which gun restrictions were lifted.

And it's also a piece with the conservative justices' concerns that federal agencies have gained too much power and are overreaching.

AMNA NAWAZ: It's been reported there are about 520,000 bump stocks in circulation when the Department of Justice changed its classification, effectively pulling it from the market.

And we asked Chip Brownlee, who's a reporter with an organization called The Trace that covers gun violence, about the potential impact of this decision.

Here's what he had to say.

CHIP BROWNLEE, The Trace: We saw these devices be used in the deadliest mass shooting in American history.

And so I think if you have somebody who is intent on committing a crime like that and gets their hands on one of these devices, they can essentially take their gun from a gun that shoots 60, 70, 80 rounds per minute to a gun that shoots 500, 600, 700 rounds per minute.

AMNA NAWAZ: Marcia, did that potential impact come up in any of the justices' questions or their discussion?

MARCIA COYLE: Well, certainly, during oral arguments, the justices were keenly aware, I believe, of the impact of bump stocks and what they can do.

But, again, they were focused on the text, the language of the Bureau of ATF's rule and whether it encompassed bump stocks as machine guns.

AMNA NAWAZ: We also know there are a number of federal firearm possession-related cases pending either before the Supreme Court or making their way through appeals courts right now.

One of the biggest is the United States v. Rahimi.

What's at stake there?

MARCIA COYLE: That's the federal ban on possession of guns by anyone who is under a domestic violence protective order.

It's going to be a fascinating case.

It is a Second Amendment case.

Lower federal courts said, using Justice Clarence Thomas' new test for Second Amendment, that there was no historical analog or anything in history that allowed such a ban to go forward.

So that could be decided this next week, any time before the end of the term.

AMNA NAWAZ: Marcia, we know there are a number of key issues on other cases still before the court.

What other kind of issues and rulings could we see this term?

MARCIA COYLE: Well, obviously, one of the most closely watched cases is Donald Trump's claim of absolute immunity from criminal prosecution.

Besides that, there are two major social media cases involving the First Amendment.

There's also several big cases involving federal regulatory agencies and their power, their authority.

The court is a little bit behind right now.

Usually, it tries to wrap up the term by the end of June, but there's still a lot left to decide.

AMNA NAWAZ: That is our Supreme Court analyst, Marcia Coyle, joining us tonight.

Marcia, always great to see you.

Thank you.

MARCIA COYLE: My pleasure.