AMNA NAWAZ: For more on the fallout from today's top stories, I'm joined by our Politics Monday team.

That is Amy Walter of The Cook Political Report With Amy Walter and Tamara Keith of NPR.

Great to see you both.

(CROSSTALK) AMNA NAWAZ: Tam, kick us off here.

I want to begin with that stunning Atlantic report by Jeff Goldberg about being added to a national security group chat about military operations unfolding on Signal.

What kind of reaction are we seeing among lawmakers to this?

TAMARA KEITH, National Public Radio: I think some very telling reaction is from the president of the United States, who was asked about it and essentially said, I don't know.

He said, you're telling me about it for the first time.

This was hours after the story broke and he's claiming not to have been briefed on this major national security breach.

You have lawmakers from both sides of the aisle, bicameral, all of it, concerned, very concerned about this because this was a breach.

And the question is, in an administration where the president of the United States has given himself, his White House broad authority to give security clearances to pretty much anyone they want without going through the process, are they going to take this seriously or not?

AMNA NAWAZ: Amy, what's your take on that?

They will take this seriously or not?

AMY WALTER, The Cook Political Report: Well, I think the first place we're going to look is, what do Republicans in Congress decide to do?

I think it's pretty clear that, had there been a Democratic president in office, that this happened under their watch, I would expect to see Republicans rise up and say there must be hearings here.

Remember, Congress is a co-equal branch.

Their job is to hold the executive branch responsible and to dig into these sorts of incidents.

Now, Democrats right now are calling for these level of hearings.

We're not hearing that from Republicans yet.

They come back today, tonight.

And I think that would be something that you could see.

We have these conversations a lot on this between the three of us about whether we're seeing an adequate position when it comes to the three branches, whether the legislative is holding the executive accountable.

Where does the judicial fit into this?

Here is a perfect example where the legislative could be holding the executive accountable for this.

I don't expect to see it happen, but maybe.

AMNA NAWAZ: We shall see.

Well, meanwhile, while I have you both, I want to ask you about events over the weekend.

Thousands of people we saw a turn out to a rally in Denver, Colorado.

It was headlined by Congresswoman Alexandria Ocasio-Cortez and Senator Bernie Sanders.

Tam, as you saw, it was billed as part of their Fighting Oligarchy tour.

What do you take away from the size of the crowd, from the reaction of the crowd, and also just the messaging that Sanders and AOC were giving there?

TAMARA KEITH: Yes, I think that there is a lot of pent-up Democratic energy looking for a place to go.

There -- I mean, among voters, among Democratic voters who are deeply frustrated with what they're seeing out of Washington, wondering, where is the leadership?

What is the party that they voted for and followed?

What is that party doing?

And it is notable that Bernie Sanders is an independent and he is both -- caucuses with Democrats, but is also quite critical of Democrats.

In terms of the message, a lot of the economic message is something that other Democrats do actually want to -- it's a very similar message to what other Democrats are looking to push headed into the midterms, as President Trump ran on bringing down grocery prices and other prices.

And prices are still high.

It's a contrast that other Democrats are trying to also figure out how to make.

AMNA NAWAZ: Amy, when you see this, we have talked a lot about what direction the Democratic Party will take.

Does this tell you what direction it's going to take?

AMY WALTER: Well, it's interesting.

This is less ideological than it is stylistic.

It is about the fight itself, not over the issues that they're fighting for.

As Tam said, it is correct.

What you're hearing from Chuck Schumer and what you're hearing from Bernie Sanders on making the economy the centerpiece, and specifically holding the Trump administration responsible for many of the policies they want to put forward and may ultimately put forward, that's going to be similar.

It's the way in which they go about making the case.

And I think we will see whether what is going on right now at these town halls is a sign of broader dissatisfaction with Democratic voters at the way that the leadership in Washington is handling Donald Trump.

It will show up, I think, first and foremost, in party primaries.

We're going to start to see folks announce for congressional seats soon enough.

And will these primaries, much like we saw when Republicans were in -- they were not in the White House, they were trying to get back in the White House, will we see something similar where we will have something of a Tea Party?

We saw back in those days in the 2009, 2010, and of course, with Trump, this idea, the same thing.

We need to see people fight more.

In many cases, some of those fighters turned out not to be great general election candidates.

That's a big question going forward, I think, for Democrats in this next few months.

AMNA NAWAZ: All right, that is Amy Walter of The Cook Political Report With Amy Walter and Tamara Keith of NPR joining us, as always, for Politics Monday.

Thank you to you both.

TAMARA KEITH: You're welcome.

AMY WALTER: You're welcome.