Former Obama adviser Dan Pfeiffer said that a leaked polling memo “shook Democrats in their boots” in a Wednesday Substack post.

The polling memo from Open Labs, leaked to Puck News, showed how President Biden’s support was sliding following his panic-inducing debate performance Thursday.

The Open Labs memo noted the “largest single-week drop” in Biden’s vote share since it began horse-race tracking in late 2021, which it noted came as Biden already faced a “challenging” election landscape before the debate.

Among the key findings was that 40 percent of Biden voters in 2020 said he should end his campaign, up from 25 percent in May.The poll also showed Biden’s vote share falling in every important swing state, with Trump holding a roughly 7-point lead in both Michigan and Pennsylvania. And it noted that Democrats other than Biden were outperforming the president in a horse race against Trump.

Polls released since the debate have been mixed, with some showing little change in voter attitudes after the debate. But Pfeiffer in his newsletter said that multiple polls on Monday started to paint a more worrying picture for Biden.

“However, the poll that really shook Democrats in their boots came from Open Labs, a highly respected Democratic polling operation that works with campaigns and Super PACs,” said Pfeiffer, also a co-host of the popular progressive podcast “Pod Save America.”

“The poll made the rounds among Democrats for a couple of days. I had four Democratic operatives share it with me on Tuesday.”

“Look, this is just one poll and polling can be very noisy in the aftermath of a major event like the debate,” Pfeiffer wrote.“But it’s hard to find an outfit more respected in Democratic circles, so folks are taking this one very seriously. The results are clearly driving folks inside Washington to push the President’s team for answers, and it has led vulnerable Democrats to begin distancing themselves from Biden.”