Fox News host Tucker Carlson said insiders in the Joe Biden presidential campaign believe he will not be mentally fit to be president come Election Day.

While appearing on the Charlie LeDuff podcast, Carlson claimed that Biden insiders told him they don't believe the former vice president has the mental fortitude to last until the 2020 election in November, speculating that the Democratic Party may revoke his potential nomination.

"I sincerely and totally believe that Joe Biden will not be the Democratic nominee on Election Day," Carlson began.

"How does that math work?" another podcast host pressed. "It's not about math. It's about will," Carlson said, saying the Democratic Party is "intent on taking power."

"Two competing imperatives: We've got to win, but we've got a guy who can't win. Therefore, they're going to replace him," Carlson continued. "He's not going to make it, and the people around him know that. Trust me, I know them. And I know they know it, because they've said it to me."

Carlson went on to estimate that New York Gov. Andrew Cuomo is "most likely" to replace Biden for the Democratic nomination.