Sen. Elizabeth Warren, D-Mass., released a video testimonial on X Sunday explaining why she's backing Vice President Kamala Harris as the new Democratic nominee.

"She is ready to step up, bring our party together, go toe to toe with Donald Trump and win in November," Warren said in the video, in which she speaks directly to the camera.

"Kamala has been a ferocious warrior on the issue of abortion and under Kamala's leadership we are going to get Roe V. Wade back into the law of the land," Warren said.

"When you're up against a convicted felon who better than a former prosecutor to take it straight to Donald Trump," she continued. "I'm here for Kamala because Kamala has been here for the American people year after year after year."

-ABC News' Allison Pecorin

In an interview with ABC News on Sunday night, major Biden donor and supporter John Morgan said that if Vice President Kamala Harris is the nominee, he won't fundraise for the Democratic ticket.

"It's one thing to vote for somebody; it's another thing to raise millions of dollars for somebody; you have to really be in," Morgan, a high-profile Florida lawyer, told ABC News.

Morgan, who says he's a "Biden/Manchin type Dem," told ABC News he was all in on Biden but felt Harris would be too far left and lose in November.

"If Trump World could pick anybody to run against, I think they pick her," he said.

Morgan told ABC News he had already informed the Biden National Finance Committee that he was resigning from his fundraising efforts after Biden endorsed Harris.

"If she's a nominee, Mar a Lago has a real big party that night," he added.

-ABC News' Will Steakin

Pro-Trump super PAC spent $30 million on ads attacking Biden

Pro-Trump super PAC Make America Great Again spent $30 million on ads attacking President Joe Biden this election cycle, Federal Election Commission records show.

The super PAC has also spent $18 million supporting former President Donald Trump.

It's unclear how much the Trump campaign, which is a separate entity from the super PAC, spent on ads specifically attacking Biden, as the campaign doesn't disclose that information.

The Trump campaign has sparingly placed television ads since the primary season.

-ABC News' Soo Rin Kim, Lalee Ibassa and Kelsey Walsh

Former Democratic National Committee Chairwoman Donna Brazile told ABC News' David Muir on Sunday night that Joe Manchin, the independent senator from West Virginia, had reached out to "inquire about the news" of President Joe Biden's exit from the presidential race.

Two sources told ABC News earlier Sunday that Manchin was considering reregistering as a Democrat to run against Vice President Kamala Harris for the presidential nomination.

In the interview, Brazile also said the DNC is committed to the virtual roll call that would wrap up by Aug. 7 -- more than a week before the convention starts.

-ABC News' Rick Klein