AMNA NAWAZ: The first two weeks alone of the Trump administration have brought dramatic proposals and some unprecedented changes in our systems of government.

Tonight, we begin a new series of interviews called On Democracy, taking a step back to look at big questions around our laws, institutions and norms and how they're changing.

We begin with Barton Gellman, a longtime journalist and senior adviser at the Brennan Center for Justice.

That's a nonpartisan think tank at New York University's School of Law.

Bart Gellman, welcome back to the "News Hour."

Thanks for being with us.

BARTON GELLMAN, Brennan Center for Justice: Thank you.

AMNA NAWAZ: Bart, I want to begin with these tabletop exercises you and your colleagues ran last May and June role-playing both a Democratic and Republican potential presidency.

On the Republican side, you looked at what would happen if Donald Trump came into office and made good on a lot of the public promises and pledges he made, how the system of checks and balances would work.

So how does what you have seen over the last two weeks-plus line up with what you saw back in those exercises?

BARTON GELLMAN: So we did five different tabletop exercises.

Two of them were called Everything Everywhere All at Once.

And those are the ones that Trump is going through with, in which he is launching attacks on multiple fronts all over the federal government against the government itself.

And he is doing so baldly in defiance of the law and in some cases the Constitution.

He is firing people he doesn't have the power to fire.

Or he's firing people without giving them hearings or reasons that are required by law.

He tried to stop $3 trillion of payments that Congress had appropriated, when it is Congress under Article I of the Constitution that has the power of the purse, not the president.

He has fired inspectors general.

This resembles basically the worst case we had in our tabletop exercises.

AMNA NAWAZ: Was there anything that you didn't include in your exercises that you have seen in the last couple of weeks that's particularly concerned you?

BARTON GELLMAN: Well, we did not anticipate that Trump would off-load so much presidential power onto a billionaire in the person of Elon Musk.

We did not anticipate that a private citizen would be given access to the entire Office of Personnel Management files and the Treasury payment system that covers $3 trillion.

We don't believe that's lawful, and I think it'll take a little time for courts to come to that conclusion.

AMNA NAWAZ: That kind of access to government and sensitive and classified information by Elon Musk and his team, it's been described to us, especially with regards to what we have seen at the USAID, as state capture.

Is that how you see it?

And is that kind of thing easily replicable across other agencies?

BARTON GELLMAN: Look, if Elon Musk is going to go into any given agency and assert the power to take control of their computer system with system administrator privileges, that just gives enormous power to retrieve, create, and even alter data.

And we don't know what he's doing with that.

Some of that data would be potentially very valuable to Elon Musk's private interests.

Is he making copies of it?

Some of that data represents, for example, the questionnaires filled out by four million people who have classified clearances, in which they answer every kind of personal question there is, including what could be used to blackmail you.

And that's in these files that he has access to now.

AMNA NAWAZ: Limiting some of Musk's access, halting the freezing of federal funds, issuing injunctions on birthright citizenship, and so on, are the courts here, as you see it, sort of the most robust guardrail?

BARTON GELLMAN: Well, they are the only coordinate branch of government right now that is not fully under the control of Donald Trump and the Republican Party.

So he's captured both houses of Congress.

And although he has appointed a lot of judges in his first term, and although he has a very friendly Supreme Court sitting on top, the judges are still -- and this is judges appointed by multiple presidents -- are still trying to enforce basic rule of law.

Trump is simply doing things that are flatly, on their face, illegal and seeing what happens.

AMNA NAWAZ: Bart, if lawmakers, and specifically Republican lawmakers, aren't acting as the guardrails you expected to see, the courts themselves will take a while to play out here in terms of those cases.

Are there other guardrails that you saw in your exercises or expected to see in real life that you haven't yet?

BARTON GELLMAN: Well, there are other guardrails.

There are other points of leverage.

Trump really cares about public opinion and his polling numbers.

He really cares about the stock market.

So, when he does something that crashes the market, he will pay a price for that.

The idea that he would pardon all the criminals who rioted and mobbed at the Capitol on January 6, more than 60 percent of Americans disapprove of that.

The fact that he then goes on to try to fire everyone in the Justice Department who participated in prosecuting those people also very unpopular.

And I am expecting that there will be at some point a backlash against these sort of lawless actions.

AMNA NAWAZ: You know, we need to underscore here we are talking about a democratically elected leader in our president right now.

Half of all voters did vote for him, not despite what he said and promised to do, but because of what he said and promised to do.

Does this say to you that America is in sort of a strongman era, that all of these actions that concern you are exactly what people wanted to see?

BARTON GELLMAN: There is some percentage of the electorate that likes a strongman, that likes authoritarians, that likes the idea that let's get someone who's going to cut through all the nonsense and get things done.

But that's always a minority.

I don't think it's even a majority of MAGA.

People felt that the country was on the wrong path.

People did not approve of Joe Biden.

People were very worried about things like inflation.

But Trump is not lowering the price of eggs.

Trump is firing the watchdogs whose job it is to prevent waste, fraud, and abuse in the federal government.

That's exactly what he claims to be trying to prevent, is waste, fraud, and abuse.

And I just don't believe that there's a majority of Americans who said, yes, I want the president to come in and break the law.

AMNA NAWAZ: Barton Gellman of the Brennan Center for Justice.

Bart, thank you so much.

It's good to speak with you.

BARTON GELLMAN: Thank you for having me.