Senator Feinstein is facing calls for her resignation from Democrats this week, resurrecting the decades old discussion of the Senate as the best nursing home in the country.

The 89-year-old Californian agreed under pressure this week to allow another Democrat to take her place on the Senate Judiciary Committee while she recovers in her home state from what she says is a bad case of shingles. Her recusal came after she missed some 60 of 82 votes this year in the Senate due to health problems.

Ms. Feinstein’s absence has held up key votes in the Senate Judiciary Committee that have ground to a halt the appointment of new liberal judges, a key priority for the Democrats. As a result, Ms. Feinstein said Wednesday that she’s called on the Senate majority leader to appoint a temporary replacement for her on the committee.

“I understand that my absence could delay the important work of the Judiciary Committee, so I’ve asked Leader Schumer to ask the Senate to allow another Democratic senator to temporarily serve until I’m able to resume my committee work,” Ms. Feinstein said.

Ms. Feinstein’s recusal comes after she announced under pressure in February that she would not seek re-election in 2024, after she was criticized by progressives for being insufficiently antagonistic during the Judiciary Committee confirmation hearings for two Supreme Court nominees, Brett Kavanagh, 58, and Amy Coney Barrett, 51. Her announcement came after a series of anonymously sourced press reports that described her as suffering from dementia, an allegation the senator denied.

Declining to run for re-election was apparently not enough for Ms. Feinstein’s liberal critics, who view her as a vestige of the more moderate, congenial Senate of yore and want her gone immediately and replaced by someone more effective, and partisan.

Leading the charge is a progressive Democratic representative of California, Ro Khanna, who at 46 is just over half Ms. Feinstein’s age. Mr. Khanna said in a tweet Wednesday that “it’s time for Senator Feinstein to resign.”

“We need to put the country ahead of personal loyalty. While she has had a lifetime of public service, it is obvious she can no longer fulfill her duties,” Mr. Khanna said. “Not speaking out undermines our credibility as elected representatives of the people.”

Mr. Khanna’s call was echoed by a Democratic representative of Minnesota, Dean Phillips, 54, who said that despite Ms. Feinstein’s contributions, her inability to perform her job is unacceptable.

“I agree with Ro Khanna — Senator Feinstein is a remarkable American whose contributions to our country are immeasurable,” Mr. Phillips said. “But I believe it’s now a dereliction of duty to remain in the Senate and a dereliction of duty for those who agree to remain quiet.”

The pressure on Ms. Feinstein recalls a similar situation in 2001 when Republicans were faced with the physical and mental decline of their longest serving member at the time, Strom Thurmond (1902-2003).

In 2001, nearing the end of the legendary senator of South Carolina’s career, Senator Hollings, also of South Carolina, alleged that Thurmond was using the Senate as a “nursing home.”

The Democrat 79 at the time, said that the situation with Thurmond, then 98, was “sad because the poor fellow doesn’t have any place to go” after serving 46 years in the Senate at that point.

“Someone has said the best nursing home is the U.S. Senate,” Hollings said at the time. “He’s got a car, a place to stay and somebody over there at night at the apartment with him. If he’s well enough, he’s in the pool for a few laps.”

Hollings went on to say that “there’s no question” that Thurmond was mentally diminished, adding that “he’s not mentally keen.”

“He’s alert, he’s awake, and they get him to votes and lead him around,” Hollings said, though he stopped short of calling on Thurmond to step down.

While some of the more aged senators are reportedly preparing for retirement, such as Minority Leader McConnell, 81, who’s lately been sidelined due to a fall, no one’s situation has become as urgent as Ms. Feinstein’s.

As it stands, it’s not clear when she will return to the upper chamber. Other senators who have been absent recently for health reasons, such as Senator Fetterman, 53, who took a leave for depression, and Mr. McConnell are expected back in the near future.

Not all Democrats, though, are calling on Ms. Feinstein to step down. A former speaker of the House, Nancy Pelosi, 83, who is of similar vintage as Ms. Feinstein and is also a very wealthy San Franciscan, has said that Ms. Feinstein “deserves the respect to get well and be back on duty.”

“It’s interesting to me,” Ms. Pelosi said. “I don’t know what political agendas are at work that are going after Senator Feinstein in that way.”

It’s not often that a Senate seat in California opens up, and a fierce competition is already beginning for Ms. Feinstein’s seat, with two prominent liberal Harvard, Stanford and Yale graduates in their 40s, Adam Schiff and Katie Porter, already declared. If Ms. Feinstein were to retire now, allowing Governor Newsom to appoint a successor, it could potentially forestall an internecine Democratic Senate primary the likes of which will have not been seen in California for decades.