The Democratic National Committee is claiming it has raised $6.5 million in grassroots donations in the 24 hours after President Biden’s endorsement of Vice President Harris on July 21.

The DNC said $1 million was donated in the 5 p.m. hour alone for what they’re claiming is a record for its best online fundraising day of all time.

The DNC is making a significant push in battleground states, investing an additional $15 million into those crucial states this month to fund new field offices, build data infrastructure, mobilize volunteers and strengthen coordinated campaigns.

“Democratic voters, volunteers, and grassroots donors are fired up," chairman Jaime Harrison said in a memo. "We are confident that in our battleground states, Democrats will win up and down the ballot in November."

-ABC News' Gabriella Abdul-Hakim

Kentucky Gov. Andy Beshear spoke on Sunday at the opening of Kamala Harris' campaign office in Forsyth County, Georgia.

The possible VP pick for Harris has been an effective surrogate for the vice president’s White House bid over the weekend, coming to the metro Atlanta event fresh off of a stump in Iowa on Saturday night.

The red-state governor introduced himself to the Southern audience on Sunday while boosting Harris’ candidacy and taking a number of swipes at Trump’s Vice Presidential pick, JD Vance.

"Are you ready to beat Donald Trump? Are you ready to beat JD Vance? Are you ready to elect Kamala Harris president of the United States of America?" Beshear asked the crowd, adding, "Let's win this race,"

"Let me tell you just a bit about myself," Beshear said. "I'm a proud pro-union governor. I'm a proud pro-choice governor. I am a proud pro-public education governor. I am a proud pro-diversity governor and I'm a proud Harris for president governor," he added.

Calling out Vance, Beshear said, "Just let me be clear. JD Vance ain't from Kentucky. He ain't from Appalachia. And he ain't gonna be the vice president of the United States."

-ABC News' Isabella Murray

Former Vice President Al Gore endorsed Vice President Kamala Harris on Sunday.

"As a prosecutor, [Kamala Harris] took on Big Oil companies -- and won. As [VP], she cast the tie-breaking vote to pass the most significant investment in climate solutions in history, the Inflation Reduction Act. That's the kind of climate champion we need in the White House," he wrote on X.

"With so much at stake in this year's election -- from strengthening democracy in the US and abroad, to expanding opportunity for the American people, to accelerating climate action -- I’m proud to endorse Kamala Harris for President," he added.

-ABC News' Oren Oppenheim

During a quick stop at a diner in Minnesota on Sunday morning, Sen. JD Vance on Sunday spoke about his past criticisms of former President Donald Trump.

When asked by ABC News if he and Trump have talked about his past criticism of the former president, Vance said yes, adding that Trump "doesn't care about what I said eight years ago."

"I mean, look, President Trump and I have talked a lot about this," Vance said. "In fact, I sometimes joke that I wish that he had the memory of Joe Biden, because he's got a memory like a steel trap, and he certainly remembers criticisms that people have made."

"But this is where the media, I think, really misses Trump -- Donald Trump accepts that people can change their mind, and you ask, 'Why did I change my mind on Donald Trump?' Because his agenda made people's lives better," Vance said.

"This whole thing is not about red team versus blue team or winning an election for its own sake. It's about getting a chance to govern so that you can bring down the cost of groceries, close that border and stop the fentanyl coming across our country for four years,” Vance continued, saying he was "wrong" about Trump.

"He did a better job of that than anybody that I've ever seen as president in my lifetime. So I changed my mind, because he did a good job. And that's what you do when people do a good job and you're wrong. I've talked to President Trump a lot about it, but look, he, I mean, he just, he doesn't... He doesn't care about what I said eight years ago. He cares about whether we together [and] can govern the country successful.”

When asked again if the two have talked about the subject, specifically in the last week since his comments have resurfaced, Vance admitted that they haven't spoken about it and their conversations have focused on the race ahead.

-ABC News' Kelsey Walsh, Soorin Kim and Hannah Demissie