In the last 24 hours Future Forward, the preferred super PAC that previously backed President Biden's reelection bid and now Harris' election bid, claims it has secured commitments of $150 million from donors who were threatening to withhold their donations after Biden's debate performance, according to a senior aide at Future Forward.

The super PAC had already reserved $250 million in TV and digital advertising earlier this year.

"Future Forward will continue working to make sure Donald Trump is defeated in this election and those dangerous consequences are never felt by the American people," the senior aide told ABC News.

-ABC News' Gabriella Abdul-Hakim, Fritz Farrow and Will McDuffie

President Biden plans to campaign in battleground states "very aggressively" with Vice President Harris as soon as the doctor gives him the COVID "all-clear," according to a senior administration official.

Biden tested positive for COVID last week.

The president will first return to the White House, then will hit the trail in the coming weeks to campaign for and with Harris, the source added.

The president is still expected to deliver remarks later this week and meet with Israeli Prime Minister Benjamin Netanyahu at the White House. The timing of all of this, the source said, is dependent on Biden's COVID recovery. But the source said they are "hopeful" it will be later this week.

The source added that they want to make sure Biden's "voice" is ready to go and that he can clearly deliver his message.

The senior administration official emphasized that Biden is still "going to finish the job" and that his priorities will remain the same. Part of finishing that job, this person added, is making sure Harris gets elected.

Another official said the president is still "full steam ahead" on his legislative priorities.

-ABC News' Selina Wang

Former House Speaker Nancy Pelosi endorsed Vice President Kamala Harris for president on Monday.

"Today, it is with immense pride and limitless optimism for our country's future that I endorse Vice President Kamala Harris for President of the United States," she wrote in a statement.

Read more here.

Michigan Gov. Gretchen Whitmer, speaking to a local station's reporter on Monday, said she would not take the vice presidency if offered and that she does not plan on leaving Michigan.

"No. I am not planning to go anywhere,” Whitmer said when asked if she is prepared to take the vice presidency if it were to be offered to her.

When asked to confirm that, if offered the position, she would not take it, Whitmer said, "I am not leaving Michigan. I am proud to be the governor of Michigan. I have been consistent. I know everyone is always suspicious and asking this question over and over again; I know you're doing your job. I am not going anywhere."

-ABC News' Rick Klein