GEOFF BENNETT: Welcome to the "News Hour."

Vice President Kamala Harris was in Houston today, honing her campaign message one day after President Biden explained why he exited the presidential race.

Harris' likely nomination has former President Donald Trump and his team racing to shift their strategy following Mr. Biden's withdrawal.

Our Laura Barron-Lopez has more.

LAURA BARRON-LOPEZ: This morning, Harris in Houston addressing the first labor union to formally endorse her candidacy for the White House.

Harris only mentioned her opponent's name once.

KAMALA HARRIS, Vice President of the United States (D) and U.S. Presidential Candidate: Donald Trump and his extreme allies want to take our nation back to failed trickle-down economic policies.

(BOOING) KAMALA HARRIS: Back to union busting.

(BOOING) KAMALA HARRIS: Back to tax breaks for billionaires.

LAURA BARRON-LOPEZ: But drew a sharp contrast to Trump throughout, boiling the election down to one question.

KAMALA HARRIS: What kind of country do we want to live in, a country of freedom, compassion and rule of law or a country of chaos, fear and hate?

LAURA BARRON-LOPEZ: That question answered in her first campaign video.

KAMALA HARRIS: We choose freedom.

LAURA BARRON-LOPEZ: Released early today, it also lays out the future Harris sees for the country, once again referencing Trump.

KAMALA HARRIS: We choose a future where no child lives in poverty, where we can all afford health care, where no one is above the law.

LAURA BARRON-LOPEZ: It all comes a day after President Biden's Oval Office address justifying his seismic decision to drop out of the race.

JOE BIDEN, President of the United States: I have decided the best way forward is to pass the torch to a new generation.

That's the best way to unite our nation.

There's also a time and a place for new voices, fresh voices, yes, younger voices.

And that time and place is now.

LAURA BARRON-LOPEZ: Meanwhile, the former president scrambles to pivot his attacks from Biden to Harris.

QUESTION: Mr. President, welcome back.

LAURA BARRON-LOPEZ: In a phone interview on "FOX & Friends" this morning, Trump responded to Harris' messaging against him.

DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: I get a kick out of one thing.

They say, sir, be nice.

He just got hit with a bullet.

Maybe he's changed.

Be nice.

And I'd love to be nice, but I'm dealing against real garbage when you hear that.

Lying Kamala Harris.

LAURA BARRON-LOPEZ: That played off of remarks last night from the former president's first rally since Biden dropped out.

Trump portrayed Harris as a liberal extremist.

DONALD TRUMP: So, if you want socialist health care, nation-wrecking inflation, the death of American energy, and a lying radical left liberal San Francisco extremist as your commander in chief, then Kamala Harris is your candidate.

She's the one for you.

(BOOING) LAURA BARRON-LOPEZ: And incorrectly labeled her as Biden's border czar, while using demonizing rhetoric toward migrants.

DONALD TRUMP: If border czar Harris stays in charge, every week will bring a never-ending stream of illegal alien rapists, bloodthirsty killers, and child predators to go after our sons and our daughters.

LAURA BARRON-LOPEZ: In reality, migrant crossings are down 55 percent since new asylum restrictions took effect seven weeks ago,the Homeland Security Department said Thursday.

This afternoon, the vice president was back in Washington for a meeting with Israeli Prime Minister Benjamin Netanyahu.

She did not attend his speech to Congress yesterday, her campaign citing a scheduling conflict.

As she campaigns, Harris will have to continue navigating one of the toughest foreign relationships for President Biden, one that's cost him some support within the Democratic Party and in key battleground states.

It will now fall on Harris to bridge the gap ahead of November.

And just four days into her campaign for president, Vice President Harris is starting to see a surge of support and new openness from key voting blocs that could ultimately determine the election.

GEOFF BENNETT: Well, let's talk more about that Laura because President Biden, as you well know, won women voters by roughly 57 percent in 2020.

How is the Harris campaign trying to capitalize on that success and reach out to that voting bloc?

LAURA BARRON-LOPEZ: Just in the few short days since she launched her campaign, Geoff, they have held nonstop calls with women, be it Black women, Latinas.

Tonight, they're going to hold a call with white women organizers and grassroots organizations across the country.

One on Sunday with Black women organizers, 44,000 Black women joined that call that had campaign officials on it.

And within the few hours of that call, they raised $1.5 million while people were on that call.

And then they had a one with Latinas just last night that roughly 4,000 Latinas joined, and they raised $118,000 on that call.

So the campaign is really hitting the ground running trying to mobilize women across the board.

GEOFF BENNETT: I know you spoke - - speaking with key organizers in multiple states today.

What did they tell you?

LAURA BARRON-LOPEZ: I spoke with LaTosha Brown.

She's the co-founder of Black Voters Matter in Georgia.

She helped lead that call with 44,000 Black women and.

She said she's never seen this level of excitement.

She compared it to when Barack Obama ran in 2008, saying that it's just seismic.

And she said that Harris has a history of engaging with a number of key constituencies from Black women to Asian American voters and women across the board.

LATOSHA BROWN, Co-Founder, Black Voters Matter: As a vice president has been leading on two issues that I think Black women care deeply about.

That's reproductive rights and voting rights.

She has a particular kind of guilty young people, because there were some young people that, if there was a concern about the campaign, there were young people who are deeply, deeply upset with this current administration about Gaza.

LAURA BARRON-LOPEZ: LaTosha Brown said that one of the young people she's been talking to was her niece, who had started to say she was actually on board, when previously her niece was not necessarily happy about President Biden running.

And I also spoke to an Arizona organizer, a Latina there, who said that the shift has already happened when they have been knocking on doors, that they used to hear questions about whether or not President Biden was going to stay in the race.

And now they're more energized and some undecided Latinos in that state are saying that they're curious about Harris and that they want to learn more about her.

GEOFF BENNETT: Well, let's return to this issue of young voters, how they view the Harris campaign.

What's your reporting suggest about that?

LAURA BARRON-LOPEZ: So we spent some time in Michigan, my producer, Shrai Popat, and I.

And in April, we held a roundtable with young voters under the age of 30, including two young women of color.

And one of them, Saba Said (ph), we checked in on, she's an uncommitted voter, those voters that are not happy about President Biden's response to Israel-Gaza.

And she said that she's unsure if she will vote for Harris, but that she's much more open to her than she was to President Biden.

And then we also checked in with a young Black woman, Melinda Billingsley (ph), who said that Biden was too moderate for her, but that she - - If the election were held today, she would vote for Harris.

And so she hopes that she hears more from Harris about criminal justice reform.

GEOFF BENNETT: Well, that's interesting because Republicans are trying to paint Kamala Harris, the vice president, as being far more progressive than President Biden.

This line that she's a San Francisco liberal, I keep hearing over and over again.

Unpack that strategy for us, the Trump campaign strategy, and trying to define the vice president.

LAURA BARRON-LOPEZ: Well, they have been really rushing to try to define her after -- and some of it is repeated attacks that they used on President Biden.

But one thing that they have been doing a lot, Geoff, is they have been calling Vice President Harris a DEI higher, diversity, equity, inclusion, higher, including, including -- and that's included some Republican lawmakers, allies of Trump.

And Trump has also himself called Harris -- quote -- "dumb as a rock."

He did that this week on TRUTH Social, really questioning her qualifications for the job.

And a lot of the Black Democratic organizers that I spoke to said that calling Harris a DEI hire is just another dog whistle.

And then Donald Trump again recently on the campaign trail repeatedly mispronounced Kamala Harris' name.

DONALD TRUMP: So now we have a new victim to defeat, lying Kamala Harris, lying, L-Y-I-N apostrophe.

(BOOING) DONALD TRUMP: For three-and-a-half years, lion Kamala Harris has been the ultra-liberal driving force behind every single Biden catastrophe.

I used to call it Biden migrant crime, but now I will probably change it to Harris or Kamala.

LAURA BARRON-LOPEZ: Her name is Kamala.

And this is something that Donald Trump did in 2020 as well.

He and his surrogates repeatedly mispronounced her name.

And a lot of Democrats have said that it's just another dog whistle.

GEOFF BENNETT: Well, what's the campaign strategy for dealing with these attacks?

Because I have spoken with Democratic strategists who say, yes, this is offensive, but Kamala Harris, the vice president, should not take the bait.

She should rise above this.

What is the campaign saying?

LAURA BARRON-LOPEZ: Well, so far, she hasn't been taking the bait.

They haven't really been responding to this at all, Geoff.

And in some cases, they're preempting it.

So in the case of past comments made by Trump's vice presidential pick, J.D.

Vance, Democrats are trying to get ahead of that, highlighting some disparaging comments he made in 2021.

SEN. J.D.

VANCE (R-OH), Vice Presidential Candidate: We're effectively run in this country via the Democrats, via -- via our corporate oligarchs, by a bunch of childless cat ladies, who are miserable at their own lives and the choices that they have made.

And so they want to make the rest of the country miserable too.

And it's just a basic fact.

You look at Kamala Harris, Pete Buttigieg, AOC, the entire future of the Democrats is controlled by people without children.

And how does it make any sense that we have turned our country over to people who don't really have a direct stake in it?

LAURA BARRON-LOPEZ: Kamala Harris is the stepmother to her husband's two children.

And her family has come out defending her, as well as Doug Emhoff's ex-wife.

And Democrats have highlighted those comments, Geoff, preempting a lot of those attacks, and essentially trying to make the argument that Republicans are out of step with voters when it comes to reproductive rights and when it comes to privacy around family planning.

GEOFF BENNETT: Laura Barron-Lopez, thanks, as always, for that great reporting.

We appreciate it.

LAURA BARRON-LOPEZ: Thank you.