GEOFF BENNETT: Welcome to the "News Hour."

President Trump has replaced White House Chief of Staff Susie Wiles with Stephen Miller, the hard-line architect of his immigration agenda, following that crushing midterm defeat.

Immigration, once a political strength for Mr.

Trump, has become a liability after two years of mass detentions, deportations, and armed agents in American cities.

AMNA NAWAZ: Mr.

Trump pledged to work with the incoming Democratic Congress, but Miller's appointment signals a doubling down on his agenda.

Miller has called Democrats a -- quote -- "domestic extremist organization."

Liz Landers reports on the appointment and the GOP's post-election reckoning.

LIZ LANDERS: Today, at the White House, President Trump defiant in his choice.

DONALD TRUMP, President of the United States: Stephen's been with me from beginning.

He gets it, very good politically, and he's a very good manager.

He will do a great job, great manager.

LIZ LANDERS: The fallout from the midterm elections reaching his inner circle.

DONALD TRUMP: I wanted to make a change.

I think Susie's done a very good job, great job, but I just wanted to make it.

Stephen's been great.

And we got to make -- we have got to make moves.

LIZ LANDERS: Trump announced this afternoon that Susie Wiles, his chief of staff, is stepping down.

She was the first woman to hold the role and was Trump's longest tenured chief of staff.

Wiles will be replaced by Stephen Miller, the current deputy chief of staff.

Miller is one of Washington's most polarizing power brokers.

He's a chief architect of the administration's immigration crackdown, but his portfolio has expanded to include national security issues.

Meanwhile, for Trump, a president who made loyalty to him a defining test of his party, criticism now comes from within it.

REP.

JAMES COMER (R-KY): And I think the Republican voters are more upset about what's going on in Iran than the Democrat voters.

LIZ LANDERS: Oversight Chairman James Comer acknowledged the unpopular war that the Trump administration launched and questioned the defense secretary's role.

REP.

JAMES COMER: I can tell you with a high level of confidence that there's a lot of questions about Hegseth.

We have no idea what the strategy is moving forward in Iran.

PETE HEGSETH, U.S.

Defense Secretary: You see, they attack me, they attack us because we are effective.

LIZ LANDERS: The secretary of defense defending himself in a video posted on social media as an outgoing Republican member of Congress could force a vote to impeach the secretary as early as next week.

PETE HEGSETH: It's all about the politics of personal destruction.

Didn't work against President Trump, and it won't work with me.

LIZ LANDERS: Republican fractures also visible beyond Capitol Hill.

FMR.

REP.

MARJORIE TAYLOR GREENE (R-GA): Oh, MAGA is completely dead.

PIERS MORGAN, FOX Nation Host: It's dead.

TUCKER CARLSON, Conservative Commentator: Well, that was a disaster, and not just a metaphorical disaster, but a real disaster.

LIZ LANDERS: The discontent isn't confined to Washington or even to Republicans.

ARTHUR YOUNG, Mississippi Voter: I just be believe people were just trying to send a message that we're tired.

LIZ LANDERS: For some voters like this one in Mississippi, the blue tsunami was a reflection of Americans' frustrations with a system they say stopped delivering for them.

ARTHUR YOUNG: We're tired of politicians enriching their pockets while everybody else is suffering.

LIZ LANDERS: But, in Mississippi, one of two Senate races, along with Alaska, that are still too close to call, the outcome remains uncertain.

SCOTT COLOM (D), Mississippi Senatorial Candidate: We're going to follow the lawful process.

LIZ LANDERS: But back at the White House today, President Trump remains optimistic.

AMNA NAWAZ: And Liz joins me now.

So, Liz, let's start with the promotion of Stephen Miller to chief of staff.

What is your reporting show the president is signaling with that move?

LIZ LANDERS: He's signaling that he's doubling down on this hard-line approach to immigration and that he is rewarding Stephen for his loyalty.

I do think that's a big factor.

The president alluded to that in the comments he made this afternoon.

Stephen Miller is a fighter.

He aggressively defends the president on television and behind the scenes, from what I have been told.

And he is MAGA through and through.

He believes in this agenda that the president is pushing.

He is so pro-MAGA that he comes across as quite anti-Democrat.

So he has made some of these recent TV appearances where he's called the Democrats the party of freaks, weirdos, losers, and crazies.

So, even though President Trump claims that he is going to work with this Democratic majority that's incoming in January in Congress, we're already hearing from Democratic leaders like Hakeem Jeffries, who will likely be the speaker, calling Miller a reckless extremist today.

The incoming chair of House Oversight, Robert Garcia, says that his committee plans to continue to investigate Miller.

AMNA NAWAZ: And we know who Stephen Miller is now.

But remind us how he got to this role.

Who is he?

LIZ LANDERS: Miller is from Southern California.

He has been politically active from a young age, really since he was in high school.

When he went to Duke, he also kind of rose to national prominence at that time because he was doing television hits on national TV defending the lacrosse team against those false rape allegations at the time.

He came to Washington.

He started working for an immigration hard-liner Senator Jeff Sessions, who was one of the first senators to endorse President Trump.

And Miller went and started working on the Trump campaign in 2015.

He was writing a lot of speeches about immigration.

Once the president won his first term in office, Miller went to go work for him, was doing a lot of that immigration policy at the time.

He was the architect of the Muslim ban, one of the most controversial policies of the first administration, also helped with that zero tolerance immigration policy of family separation.

He has been the policy chief of staff this administration.

So he has been working with the president on some of these executive orders, has been a vocal defender of that executive order that the president signed and was shot down by the Supreme Court over ending birthright citizenship.

And just one more example of Miller's very hard-line stance on immigration, earlier this year, when Alex Pretti was shot by immigration officers in Minneapolis, Miller called him an assassin, which he then had to walk back.

AMNA NAWAZ: So he is now chief of staff.

That role is different for every administration.

What has it been like under President Trump?

LIZ LANDERS: I think, for President Trump, it's more about managing the staff than it is about managing him.

I think chiefs of staff in the past have found difficulty in trying to rein him in and some of his impulses.

Instead, I have heard that Susie Wiles was an effective chief of staff because the staff at the White House really liked her and respected her and a little bit in some ways feared her at times.

She really kept the staff in line.

We saw far fewer leaks, I think, in the Trump 2.0 than we did at the first Trump administration.

For Miller's part, looking at how he's going to come into this role, he posted online this afternoon.

He said: "The mission now is more clear than ever, fight with all of our soul to support our president and defend this magnificent republic."

AMNA NAWAZ: All right, Liz Landers beginning our coverage tonight.

Liz, thank you.

LIZ LANDERS: Of course.