AMNA NAWAZ: A swirl of news at the U.S. Capitol today, where, this afternoon, the top four leaders in Congress agreed to a deal to avert a partial government shutdown for at least a week, that after one of those leaders, Republican Senate Leader Mitch McConnell, announced he will step down from leadership this fall.

McConnell's news came as Republicans on the other side of the Capitol also made headlines, questioning President Biden's son Hunter behind closed doors as part of their impeachment inquiry.

Our Lisa Desjardins has been following it all, and she joins us now.

Lisa, a busy, busy day.

Let's talk about this spending deal first.

What's in it, and has the shutdown now been averted?

LISA DESJARDINS: Yes, with two important caveats, yes, for now.

And, two, this still has to pass through both chambers of Congress.

Let's talk about this deal, what's in it.

Here's a look.

First, the deadline that was coming up the fastest, March 1, that deadline moves to March 8, so buying time to pass the bills that were about to run out of money.

So what this means is, now they're going to try and pass six separate spending bills between now and March 8.

They basically have those bills ready to go, but they need to kind of -- they need to write the text, get it out and give members time to read it.

So, the other deadline, the harder one, the March 8 deadline, as it is now, would move to March 22.

That one is harder, Amna, because, among other things, it includes the Department of Homeland Security, border spending, those kinds of things.

So that is one we will watch very closely.

This next week will be important to see if we can actually not kick the can down the road again, at least on half of these bills.

But, basically, they're buying time.

At least they agree on that.

AMNA NAWAZ: At least they agree on that.

Let me ask you now about the news from Leader McConnell, the longest-serving Senate leader in history.

Why is he stepping down and what does his stepping down mean?

LISA DESJARDINS: McConnell is a historic figure, not just because he's a master strategist.

And you could say he's the reason, for example, that Roe v. Wade was overturned because of how he handled Supreme Court nominations.

But he is also the most powerful opponent of some of Donald Trump's policies and statements in the Republican Party.

Why is he stepping down?

He says simply he is in his 80s and he realizes that now it is time for him to hand this over to a next generation.

SEN. MITCH MCCONNELL (R-KY): Father Time remains undefeated.

I'm no longer the young man sitting in the back hoping colleagues would remember my name.

It's time for the next generation of leadership.

LISA DESJARDINS: He was first elected in 1984.

He mentioned that Ronald Reagan in fact got his name wrong when he was first elected.

Now, what's going to happen here is that Senator McConnell will step down from leadership in November, he says.

There will be a fight among Senate Republicans to replace him.

He, it sounds like right now, will stay in the Senate itself.

But, Amna, this is also meaningful because what we're seeing here with Senate Republicans, that group that really has been sort of a traditional Republican force, that's changing, as we saw in the Ukraine vote.

More than 20 Republicans voted against Ukraine funding.

Those are the younger members.

Those are the folks who are more Trump, more hard right.

Mitch McConnell stepping aside changes some dynamics there.

AMNA NAWAZ: OK, what about news on the other side?

LISA DESJARDINS: Right.

AMNA NAWAZ: In the House, meanwhile, we know the president's son Hunter Biden spent some seven hours testifying behind closed doors today.

What did we learn?

LISA DESJARDINS: We need to wait for the transcript.

It's going to be a long one after seven hours of questioning, but a couple of things.

Hunter Biden did not plead the Fifth at all, even though, of course, he faces criminal charges.

He's in the midst of his own criminal proceedings.

He was responsive.

Even Republicans said he responded to most questions that they asked him.

However, it was highly contentious.

It was even messy at the beginning, both sides interrupting each other.

And Democrats say that part of the problem here was that Republicans were asking personal questions.

As for Hunter Biden, I want to read you part of his opening statement.

This is what he says his message was all day today.

He told members that he was here "today to provide the committee with the one uncontestable fact that should end the false premise of this inquiry.

I did not involve my father in my business."

And Democrats say, in fact, that's what happened all day long, that Republicans sometimes brought on personal attacks against him, but nothing against former President -- or President Biden.

Here's what Democrats said to the cameras.

REP. ALEXANDRIA OCASIO-CORTEZ (D-NY): What we just witnessed over the last hour was, I think, a deep sea fishing expedition, because the Republican case has completely fallen apart over the last several weeks.

REP. JAMIE RASKIN (D-MD): This whole thing really has been a tremendous waste of our legislative time and the people's resources.

REP. VERONICA ESCOBAR (D-TX): This is nothing more than a distraction from what Republicans don't want us to pay attention to.

They don't want us to pay attention to the fact that they cannot govern.

LISA DESJARDINS: That was across the board from Democrats.

And when you talk to staffers behind the scenes, they say they felt like there was nothing new here from Hunter Biden.

Republicans saw something a little differently.

Here's Republican Nancy Mace of South Carolina.

REP. NANCY MACE (R-SC): Hunter Biden is being defiant and also dishonest.

And his testimony, some of it, is in direct conflict with other witnesses.

And so the transcripts will be out.

I won't go into detail.

You will be able to see it for yourself.

But it's no surprise.

It's no shock that he is being that way.

And, in some cases, he doesn't recall.

He said that multiple times this morning, which, again, is not a shocker either.

LISA DESJARDINS: Here's the thing.

We definitely do want to see this for ourselves, whether there are inconsistencies or not.

Now, we know that there is very little direct evidence that Republicans have presented that President Biden knew anything about Hunter Biden's business deals.

There are two witnesses that say they think perhaps Joe Biden was going to get a cut of profits.

But today in testimony, Hunter Biden said, no, the people who said that were out of their minds for thinking that.

We will watch that.

But, right now, we don't know that there is that direct evidence right now of Joe Biden being involved in anything that was a problem.

We may find out more ourselves, because one thing we heard today was that they expect to have public hearings now with Hunter Biden.

That is the next step, as folks might remember, when we went through Trump impeachment proceedings.

Public hearings are the next step before potential articles of impeachment against Joe Biden.

AMNA NAWAZ: Lisa Desjardins quite literally covering it all on Capitol Hill.

Lisa, thank you so much.

LISA DESJARDINS: You're welcome.