WILLIAM BRANGHAM: Welcome to the "NewsHour."

A plea agreement that would have kept Hunter Biden out of prison for tax and gun charges was unexpectedly put on hold today, adding new questions to an already politically divisive deal.

Laura Barron-Lopez explains.

LAURA BARRON-LOPEZ: A tumultuous day in federal court for Hunter Biden after a judge put his guilty plea agreement on hold in Wilmington.

The legal drama for the president's son, again a subject of fierce debate in Washington.

SEN. MITCH MCCONNELL (R-KY): To the extent that it looks like the administration is treating Democrats more favorably than Republicans, I can understand why, people in the House are upset about it.

SEN. CHUCK SCHUMER (D-NY): Bottom line is, this is a prosecution being done in a fair way by a former Trump prosecutor, and I have faith in the results.

LAURA BARRON-LOPEZ: The deal was, Biden would plead guilty to two misdemeanor tax charges.

In exchange, he would not face prosecution for a felony gun charge, provided he remains drug-free for two years and does not purchase another weapon.

But, today, Biden pleaded not guilty to the two tax charges after district court Judge Maryellen Noreika, who is presiding over the case, voiced concerns early about the deal.

At the White House, Press Secretary Karine Jean-Pierre reaffirmed the president's position.

KARINE JEAN-PIERRE, White House Press Secretary: Hunter Biden is a private citizen, and this was a personal matter for him.

As we have said, the president, the first lady, they love their son and they support him as he continues to rebuild his life.

LAURA BARRON-LOPEZ: Despite the charges, congressional Republicans have accused Hunter Biden of receiving special treatment from the Justice Department... SEN. JOSH HAWLEY (R-MO): No, I mean, it sounds like it was rife with all kinds of irregularities.

LAURA BARRON-LOPEZ: ... and have targeted his business dealings with some, with House Republicans weighing an impeachment inquiry into unproven allegations that President Biden was involved.

REP. ELISE STEFANIK (R-NY): With each passing day, House Republicans' investigations uncover more and more evidence showing that Joe Biden not only knew about, but was involved in his family's illegal influence peddling scheme.

LAURA BARRON-LOPEZ: Again, those accusations are unsubstantiated.

But Republican attacks on the president and his son will almost certainly ramp up in the aftermath of today's hearing, which left Hunter Biden's legal future unresolved.

To help us understand it all, I'm joined by Glenn Thrush of The New York Times.

He's in Wilmington, Delaware, where he was inside the courtroom.

Glenn, thanks so much for joining.

Today was expected to be smooth sailing for Hunter Biden on this guilty plea deal, but that all broke down.

What happened?

You were in the courtroom.

Can you explain?

GLENN THRUSH, The New York Times: It was pretty extraordinary.

When you cover a plea deal, it tends to be the signing of some papers.

The judge tends to go through a whole list of questions that are sort of written out in advance.

But the tenor of this hearing was totally different from the start.

The judge in the case seemed utterly skeptical, nearly hostile towards this agreement, and she attacked two provisions in particular.

The first was a provision that was the gun agreement on the diversion program.

And the second, and more importantly, was this blanket immunity that the government had granted to Hunter Biden relating to any issues, not - - that appeared to relate to any issues, not just tax and gun charges, emanating from that period of time, which is roughly 2014 to 2019, when he was simultaneously earning millions of dollars a year working as a consultant for foreign countries and in the throes of a really desperate drug and alcohol addiction.

LAURA BARRON-LOPEZ: And so Hunter Biden ended up pleading not guilty to those two misdemeanor tax charges that you mentioned.

But he could still end up working out a deal with the Justice Department, right?

So can you walk us through where all those charges stand, including that potential felony gun charge?

GLENN THRUSH: I wish I knew.

I don't think anybody at this point knows.

I think Hunter Biden's lawyers at this moment are trying to figure out how to pick up the pieces.

But, yes, you're right.

The not-guilty plea is intended to be a placeholder.

It's a placeholder that could actually turn into a real plea if they don't come up with an agreement.

But, at the moment, the judge gave them two weeks to essentially overhaul this plea deal to address two particular concerns.

One is her level of involvement in overseeing the gun deal -- she thought she was given too much of a role in it -- and rewriting a provision in that immunity agreement, which she wants more narrow.

So if they're able to come up with an agreement, we could be back here in a couple of weeks for what could be a less dramatic version of today's events.

LAURA BARRON-LOPEZ: And, as you noted, the dispute between the Justice Department and Hunter Biden's lawyers centered on a question over the breadth of the immunity that he was or wasn't going to get in this deal and about whether or not he could face future criminal charges.

How likely do you think additional charges could be down the road, if they ultimately come to a deal?

GLENN THRUSH: Well, you're getting at what was probably, I think, the most interesting moment in the hearing.

The judge asked the government, in this case, one of the top prosecutors in Delaware, whether or not this investigation was ongoing.

And the prosecutor said, categorically, yes.

She then asked a series of questions, really interesting ones, asking, hypothetically, what were the potential charges apart from the tax and gun charges that might be looked at?

And one of them that she mentioned involved registering as a lobbyist for a foreign country.

That is something that has been mentioned as a potential charge that was looked into.

But it was interesting that the prosecutor did not deny that and indicated that that was one of the areas that would not be covered under the plea agreement that was submitted today.

LAURA BARRON-LOPEZ: Yes, right there, you're referring to the Foreign Agents Registration Act, which could apply to Hunter Biden.

Glenn, do we have any idea if, in the future dealings here, whether or not they have one that they ultimately come to, if the president's son could ultimately face prison time?

GLENN THRUSH: I mean, at this point in time, things are up in the air.

I would say, just generally speaking, there is a strong motive for both Biden and the prosecutors to get a deal done.

I think David Weiss, the prosecutor in this case, has invested an awful lot of his capital.

He's been on the job for a long time.

He is a Trump appointee.

He wants this thing done with.

He is currently facing a grilling at the hands of House and Senate Republicans.

So I think he would like to have this -- be past this when he goes up on the Hill to testify perhaps in September and October.

And Hunter Biden -- probably the most emotional part of today was Hunter Biden talking about his drug and alcohol addiction in the past tense.

I think he very much wants to put his legal problems in the past tense as well.

LAURA BARRON-LOPEZ: Glenn Thrush of The New York Times, thank you so much for your reporting.