Three current U.S. officials and a former U.S. official said the National Security Council toned down parts of Harris' widely covered speech. The vice president's office denied it was watered down.
A March 28 first-of-its-kind fundraiser featuring Presidents Joe Biden, Barack Obama and Bill Clinton is expected to raise more than $10 million and draw at least 3,000 people.
Critics have questioned whether the 81-year-old president and his 77-year-old opponent, former President Donald Trump, are too old to serve another term.
NBC News projects that Biden has won Michigan, where some activists had pressed voters to vote "uncommitted" because of his stance toward the war in Gaza.
The first lady issued a deeply personal email, which raised more money than any other campaign email sent since Biden launched his re-election campaign in April.
The White House is accelerating plans to blast Republicans for tanking a bipartisan measure that was far to the right of anything Democrats had supported on immigration in the past.
Joe Biden's campaign has stayed away from the issue, concerned it could further the perception the president is using the Justice Department to help his re-election bid.