GEOFF BENNETT: Welcome to the "News Hour."

President Biden tonight explained his decision to drop out of the 2024 presidential race during an address from the Oval Office.

AMNA NAWAZ: He called his time in office -- quote -- "the privilege of my life," but said it was time for a new generation of leadership.

JOE BIDEN, President of the United States: But nothing, nothing can come in the way of saving our democracy.

That includes personal ambition.

So, 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.

GEOFF BENNETT: Meantime, Mr. Biden's vice president, Kamala Harris, is moving closer to locking up her party's nomination for president.

AMNA NAWAZ: And former President Trump is already on the attack, going after her directly tonight in his first rally since Biden dropped out of the race.

Our White House correspondent, Laura Barron-Lopez, has been following all this and joins us now.

So, Laura, this address from President Biden comes three days after he decided to end his reelection campaign.

This was meant to explain what was behind that decision.

What did you take away from his remarks?

LAURA BARRON-LOPEZ: In his remarks tonight, Amna, from the Oval Office, he argued that his work merited a second term and that he per -- he implied that he personally wanted to stay on the job.

But he appeared to acknowledge that his party had been fracturing in the past few weeks following his June debate, and he said that he needed to unite the party in this critical endeavor of saving democracy.

He also said that it was time to pass on the torch to younger voices, and that he ultimately laid out the stakes, Amna, that the -- for the electorate, saying that the stakes of this election are about saving democracy.

And joining him in the Oval, Amna, were members of his family as he gave this address, including the first lady, including his daughter Ashley Biden, and his son Hunter Biden.

AMNA NAWAZ: And, Laura, we know that he only mentioned Vice President Harris once by name in those remarks.

This is obviously not meant to be a political speech there delivered from the Oval Office, but, as you said, he wants to pass the torch on to this next generation of leaders.

What should we take away from his support for Vice President Harris, how involved he might be in her campaign moving forward?

LAURA BARRON-LOPEZ: Well, giving the speech from the Oval, it can't be overtly political, as you noted, Amna.

But he said that his choice was clear, his choice was made, and that he believes Harris is tough, that she can finish the job that he started, that she's experienced.

And he presented a stark contrast between what would be a Harris presidency versus a second term for Donald Trump, asking the country if they could -- if they could just learn to disagree with each other, rather than calling each other enemies, and asking if character still matters when they're looking to a president, so posing big questions to the public there, Amna.

And, also, a White House official said that Vice President Harris watched President Biden's address from Houston, Texas, where she has been surveying hurricane recovery.

AMNA NAWAZ: We also know that Vice President Harris was in Indianapolis on official duty earlier today.

And, as you mentioned, her campaign has really hit the ground running in the last few days.

They have had record-breaking fund-raising efforts so far, rallies and events being planned out.

What's the latest on those efforts we should know?

LAURA BARRON-LOPEZ: As Vice President Harris was speaking to a historically Black sorority today, Amna, she went on the attack against Trump, saying that his second term would take the country backward, and she specifically pointed out the Project 2025 blueprint crafted by people that served in his last administration.

Her -- and her campaign is saying that, three days in, the electoral map is already expanding.

In a memo on the pathway to 270, campaign Jen O'Malley Dillon said -- quote -- "In a highly polarized electoral environment, this shift in the race opens up additional persuadable voters.

This race is more fluid now.

The vice president is well-known, but less well-known than both Trump and President Biden, particularly among Dem-leaning constituencies.

So, the campaign chair there, Amna, saying that they have an expanded universe of voters.

And compare it to just days ago, when President Biden was still in the race, and that same campaign chair, Jen O'Malley Dillon, was saying that they had to be focused on just the blue wall states, that now other states are opened up to Vice President Harris.

And she's also gaining support with the same types of Republicans that backed President Biden, like former Lieutenant Governor of Georgia Geoff Duncan, a Republican, who told me today that he is endorsing Kamala Harris and that he will do everything he can to oppose Trump.

AMNA NAWAZ: Meanwhile, former President Trump also held his first rally since President Biden ended his reelection bid.

We know that Trump campaign now has to pivot their strategy to focus more on Vice President Harris, who will likely be at the top of the Democratic presidential ticket.

What kind of messaging are we seeing from them so far?

LAURA BARRON-LOPEZ: Today, Donald Trump held his first rally since President Biden dropped out in North Carolina, and he was specifically attacking Vice President Harris on her record of immigration.

DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: Kamala's deadly destruction of America's borders is completely and totally disqualifying.

She shouldn't even be allowed to run for president, what she's done.

She's committing crimes.

No person who deliberately lets these kinds of savage criminals into America should ever be trusted with power again, should ever be trusted to be the president of our country.

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

LAURA BARRON-LOPEZ: We should note, Amna, that it is inaccurate that Vice President Harris was tasked to be the border czar.

President Biden never assigned that to her.

Instead, he asked her to work with Northern Triangle countries to address the root causes of migration, but you're hearing there the former president trying new attack lines on Vice President Harris.

AMNA NAWAZ Our White House correspondent Laura Barron-Lopez reporting tonight.

Laura, thank you.