The Chinese water torture is a particularly nasty thing, relying not on the infliction of pain or trauma but simply securing the victim in a fixed position, after which cold water is steadily dripped on the subject's head or face. It's not physically painful, but instead a mental torture, in which the steady drip, drip, drip, slowly works away at the victim's sanity.

Something like that is happening to President Joe Biden right now, with a steady drip, drip, drip of prominent Democrats dropping their ice-cold doubts about old Joe's viability onto the president's forehead.

A fourth senate Democrat called on President Joe Biden to quit the presidential race Friday, joining other 35 Democrats in Congress and a 55,000-member Washington state labor union as the president maintains his defiance and plans to keep campaigning next week.

The latest call for Biden to quit the race came from Sen. Sherrod Brown, D-Ohio, whose third re-election bid in November is considered crucial to Democrats’ efforts to hold onto a Senate majority.

Brown joins two other Democrats who spoke out about Biden as they run for re-election this year: Sen. Martin Heinrich, D-N.M., and Sen. Jon Tester, D-Mont., who is one of the most vulnerable Senate Democrats (the first senator to call on Biden to stand down was Sen. Peter Welch, D-Vt.).

Senator Brown, in a statement released on Friday, said:

“I agree with the many Ohioans who have reached out to me,” Brown added. “At this critical time, our full attention must return to these important issues. I think the President should end his campaign.”

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SEE MORE: 

What Biden Campaign Is Telling Its Staff Shows How Much It's Burying Its Head in the Sand

Biden Tweets About Trump's RNC Remarks, Reveals One Reason He's in So Much Trouble

It seems like the more Democrats look for the exits, the more Joe Biden digs in his heels, but sooner or later someone is going to have to have a heart-to-heart with the old man. The last time things got this bad for a sitting president - and the Biden administration won't care for this comparison, but it's apt - was in 1974, when a group of prominent Republicans, including Senator Barry Goldwater (R-AZ) U.S. House Minority Leader John Rhodes (R-AZ) and U.S. Senate Minority Leader Hugh Scott (R-PA) went to President Richard Nixon and told him he had lost the support of his party and, for the good of the Republican Party and the nation, he needed to resign. Nixon resigned the next day.

That is what is going to have to happen with Joe Biden. Who is the likely person to carry out this task? Kamala Harris.

For better or worse (and it's been mostly worse) she is the Vice President of the United States. While one may wonder as to how much stock old Joe really places in her opinion, she is technically the #2 figure in the Democratic Party today. It's her task to take the old man aside and tell him, "You know, Joe, you've already lost. For the good of the party and the republic, you need to resign."

It is a resignation, also, that should happen, not just a withdrawal from the re-election campaign. Joe Biden is clearly not capable and has not been for some time. Every day he remains in place is a day where the United States has, effectively, no leadership, no Commander-in-Chief, no chief executive. That's an intolerable situation.

Until that happens, watch for the defections to continue, especially after this week's roaringly successful Republican convention.

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