Top Democratic fundraisers sound the alarm after Biden's debate performance

• Top Democratic fundraisers are privately sounding the alarm about President Joe Biden's disappointing debate performance against Donald Trump.
• Just 15 minutes into the debate, some of the Democratic Party's top fundraisers had already reached out to CNBC, almost all raising concerns about Biden's debate performance.

Many of the Democratic Party's top fundraisers are privately sounding the alarm after President Joe Biden's disappointing debate performance Thursday against Republican former President Donald Trump.

"Disaster," said a Biden donor who plans to attend a fundraiser with the president on Saturday in the Hamptons.

"This is terrible. Worse than I thought was possible. Everyone I'm speaking with thinks Biden should drop out," said the person, who was granted anonymity in order to recount private conversations.

CNBC began hearing from worried Democratic campaign donors and fundraisers less than 20 minutes into the 90-minute debate hosted by CNN.

"Game over," said a longtime Democratic campaign advisor, who has been raising money for congressional leaders for over a decade and helped raise money for Biden's 2020 White House bid.

"Biden's got to leave. He's got to get out now and if he doesn't get out we're going to get f------ crushed," said the advisor. They told CNBC they planned to approach Democratic National Committee Chairman Jaime Harrison on Friday to discuss what happened at the debate.

An advisor of one of the Democratic Party's top megadonors called the debate an "absolute train wreck" for Biden. "Worse than [Ronald] Reagan in '84 or [George W.] Bush in '04 or [Barack] Obama in '12," they added.

The problems for Biden at the debate started early. He stumbled out of the gate, appearing to lose his train of