AMNA NAWAZ: Pulitzer Prize-winning reporter Devlin Barrett of The New York Times has covered federal law enforcement for more than two decades.

His new book pulls back the curtain on Trump's Justice Department and the way the president has used it as a tool to settle political scores.

I spoke earlier today with Devlin about that book, "The Department of Revenge."

Devlin Barrett, welcome to the "News Hour."

Thanks for being here.

DEVLIN BARRETT, Author: Hi.

Thanks, Amna.

Thanks for having me.

AMNA NAWAZ: So one of the key points underpinning all your reporting in the book is how different President Trump's approach is to the Department of Justice in his second term as compared to his first.

You write in the book: "His rage against the Justice Department was also deeply personal, a visceral instinctive reaction to his own experience."

What did you mean by that?

DEVLIN BARRETT: I mean, I have covered federal law enforcement for a very long time.

And one of the things you see happen over and over and over is, when a person is charged by the government, when a person is investigated by the government, that person also comes out of that experience very angry and bitter about what happened to them.

And I think one of the things that is really important about understanding what Trump is doing to the Justice Department and why is that he is a former criminal defendant who is now in charge of these agencies.

And he is still very angry and very suspicious of federal law enforcement.

AMNA NAWAZ: He describes himself at one point as the hunter now.

And within the DOJ, you report that officials there would refer to the president as the department's chief client.

What does that come to mean in terms of how they approach and do their work?

DEVLIN BARRETT: If you think about the department, the Department of Justice is different than all the other agencies in the government.

It's not like the Department of Agriculture.

It's not like the Department of Commerce, because the Department of Justice is tasked with enforcing the criminal laws of the country, basic issues of right and wrong.

And when people join the Justice Department or join the FBI, they take an oath to defend the Constitution.

What's so different about what is happening in the Trump Justice Department right now is that all those lawyers and all those agents are being told very explicitly, your oath to the Constitution means you must always do what the president wants.

And that has never been how that oath has been interpreted before.

And so that's why so many Justice Department people have left, some have been fired, and that's why there's so much turmoil inside the department.

AMNA NAWAZ: There's a new detail in the book I want to ask you about, a never-before-released secret recording of a meeting in which Emil Bove, you said, suggested that people who signed off on a motion that would dismiss this action against then-New York City Mayor Eric Adams, if anyone signed that motion, they could get a promotion.

Tell us about what happened there.

DEVLIN BARRETT: Right.

So there's a confrontational meeting early into the Trump administration, when Emil Bove meets with the Public Integrity prosecutors, a very important part of the Justice Department that handles corruption cases.

And, basically, he's at that moment of that meeting, he's already forced out a number of federal prosecutors in New York because he's trying to end a criminal case against New York Mayor Eric Adams.

AMNA NAWAZ: And they were forced out because they refused to sign.

DEVLIN BARRETT: They refused to go along with that.

They refused to put their names on a motion to dismiss their own case, saying that was wrong and they wouldn't be a part of it.

So then Emil Bove takes that same demand to the Public Integrity prosecutors.

And, in a meeting, he says, I will give you an hour, but I want two people to sign this motion.

And he really wants career prosecutors to do it.

It's important to him to have careers do it.

And he says, whoever signs this will emerge as leaders of the Public Integrity Section.

And my reporting shows that everyone in that conversation understood that to mean, if you sign this document for me in this very contentious issue in this case, I will promote you.

AMNA NAWAZ: And is there evidence that happens?

DEVLIN BARRETT: Yes, because the person who ultimately agrees to sign the motion, who does it for, I think, some understandable, not dishonorable reasons, that person does become promoted.

That person is running what's left in the Public Entirety Section today.

AMNA NAWAZ: And the recording is important because Bove is asked about this in congressional hearings.

What does he say?

First, he says he doesn't understand the question.

Then he says he doesn't remember.

But finally, he says, no, he didn't do that.

And that's really important, because the recording is clear.

And I know people who were in their original meeting who watched Bove's testimony.

And in that moment, those people certainly believed that Bove wasn't telling the truth to Congress.

AMNA NAWAZ: Can you give us a sense of what's happening among the career attorneys around these kinds of instances?

It's not the only one you document, in which people are pressured to sign off on things or take steps that they say are unethical or there's no evidence for, right?

AMNA NAWAZ: And yet they always seem to find someone who will sign off on something or will move forward with the prosecution.

So what's happening with the attorneys at this point?

DEVLIN BARRETT: What you see time and again is, career prosecutors saying you don't have the facts to support the charges you want to file here under the law, and the political leadership of the department pushing and saying, file the charges, find a way, get it done.

And what you see time and again, repeated, is that the people running the Justice Department, in a certain sense, are on a kind of fishing expedition.

That term historically means prosecutors who are just looking for dirt, and they don't have a good reason to investigate.

They're just looking for dirt.

This, I would say, is a different kind of fishing expedition.

This is a fishing expedition for prosecutors who are willing to lower standards and to charge cases that other career prosecutors will not charge.

AMNA NAWAZ: You also report on how badly depleted the work force has been within the department.

Can you quantify it?

What would you say is the current status of the Justice Department?

DEVLIN BARRETT: I mean, parts of the Justice Department are functioning almost like ghost ships at this point.

They are so understaffed and a lot of the people in charge are fairly green, fairly inexperienced.

And there has been a tremendous exodus of legal experience, legal talent.

So, for example, more than half of the lawyers in the Civil Rights Division have left.

If you look at the Criminal Division, one out of five of the lawyers there have left.

If you look at individual sections like, for example, the National Security Division, they have lost a tremendous amount of the senior lawyers.

And in that division especially -- you're talking about terrorism and espionage cases -- it's hugely important to have people who have done a lot of terrorism and espionage cases before.

And so there's a tremendous lack of personnel now within the department.

And the result of that really is, you have a great more uncertainty in the department.

You have a lot more confusion in the department as to who's doing what and why.

And you have -- one person described themselves and their colleagues as mole people, just trying to stay out of the eye of the leadership of the department.

And I would like to make one thing clear, which is that there are still a lot of very smart, very ethical people doing very good work in the Justice Department and the FBI.

There are a lot of things that the Justice Department and FBI do that really don't deal with corruption or political issues or anything like that.

And there's a lot of good work being done in those areas.

But I think, even in those areas, you talk time and time again to lawyers and agents who are terrified that any day they could get a call assigning them to some case that makes no sense and feels wrong,and they are told they have no choice but to obey.

AMNA NAWAZ: The book is "The Department of Revenge."

The author is Devlin Barrett.

Devlin, thank you so much.

DEVLIN BARRETT: Thanks, Amna.