That governor's remark adds fuel to the fire of growing calls from Democrats in Congress who are hoping Biden will allow Vice President Kamala Harris, who is 59 years old, to finish the campaign at the top of the ticket with a running mate of her own. This week, two longtime House Democrats — Reps. Lloyd Doggett (D-TX) and Raúl Grijalva (D-AZ) — publicly called for Biden to exit the race given the drumbeat of worry over his mental fitness.

"If he’s the candidate, I’m going to support him, but I think that this is an opportunity to look elsewhere," Grijalva told the New York Times on Wednesday. "What he needs to do is shoulder the responsibility for keeping that seat — and part of that responsibility is to get out of this race."

But those two public calls for Biden to end his reelection campaign could be the first of many. Martin wrote in his column that, according to unnamed "lawmakers and operatives close to them," that "the majority of congressional Democrats... want the president to drop out." He added that a "connected House Democrat" told him: "Polling will get a little worse and people are going to lose their minds even more."

According to Martin, the rift between congressional Democrats and Democratic governors could be widening. House Democrats in competitive districts who have to share a ballot with Biden are more keen to have him name Harris as a successor, in order to prevent a beleaguered Biden from dragging down Democrats' chances in down-ballot races. And some of the more ambitious governors potentially contemplating a run for the White House in 2028 are catching criticism for not doing more to push Harris to be the nominee, as a President Kamala Harris running for reelection four years from now would dash their hopes of occupying the White House.

"One example: A group of Democrats woke up Thursday to a new internal poll from must-win Wisconsin, which had Biden down seven points and only running in the 30s on a ballot with third-party candidates," Martin wrote. "As the old saying with tough votes goes, though, right now they are voting yes while hoping no."

If Biden does step down, he would have to do it relatively soon, as the Democratic National Convention will kick off in Chicago between August 19 and 22. After a nominee is designated, it will be much more difficult — if not outright impossible — for another Democrat to assemble a competitive nationwide campaign before ballots are cast.

Biden maintains that he is healthy and well and plans to continue his campaign through the November election.