Throwing the Senate’s storied civility aside, Republican Senators are pledging to obstruct Senator Feinstein’s request to be temporarily replaced on the Judiciary Committee while she recovers in California from what she says is a bad case of the shingles. Without Ms. Feinstein on the panel, the Biden Administration’s rapid confirmation of liberal judges has ground to a halt.

An associate editor at Sabato’s Crystal Ball, Miles Coleman, told the Sun that he expects the situation with Ms. Feinstein, who at 89 is the oldest member of the Senate, to be an issue that Republicans “play hard ball on.”

“With an institution like the Senate, age is something that you have to consider, that both parties have to plan for,” Mr. Coleman said.

On Monday, Senator Blackburn, the Tennessee Republican, signaled that she would not support a replacement for Ms. Feinstein on the Judiciary Committee, a process that requires a unanimous vote.

“I will not go along with Chuck Schumer’s plan to replace Senator Feinstein on the Judiciary Committee and pack the court with activist judges,” Ms. Blackburn, 70, tweeted Monday morning. “Joe Biden wants the Senate to rubber stamp his unqualified and controversial judges to radically transform America.”

Failing a unanimous vote in the committee, the only way to replace Ms. Feinstein on the committee is to bring the issue to the Senate floor and pass the replacement with 60 votes.

Over the weekend, Senator Cotton, 45, signaled that he would work to block the Senate from approving a temporary replacement to fill Ms. Feinstein’s spot on the judiciary committee, signaling that 60 votes could be an impossible threshold.

“Republicans should not assist Democrats in confirming Joe Biden’s most radical nominees to the courts,” Mr. Cotton said in a tweet.

Mr. Coleman said that, given the focus the GOP has had on capturing the courts in the recent past, he isn’t expecting any compromises from leadership.

“This is one of those things where I can see Republicans putting their foot down to make sure that Democrats have one less seat on that committee,” Mr. Coleman said.

This leaves Democrats without any real choice except waiting for Ms. Feinstein to return to the Senate, even though Ms. Feinstein asked leadership to find a temporary replacement last week. Ms. Feinstein has missed 60 of 82 votes this year, reportedly due to health problems.

In her own words, Ms. Feinstein “asked Leader Schumer to ask the Senate to allow another Democratic senator to temporarily serve until I’m able to resume my committee work.”

With Ms. Feinstein’s absence, Mr. Biden’s appointing of new judges, a process which was proceeding at a breakneck pace last year, has been ground to a halt.

Ms. Feinstein’s absence has led to some calls for her resignation from within the Democratic Party and subsequent backlash against those calls from other members of the party.

Last Week, Representative Ro Khanna, 46, publicly called for Ms. Feintein’s resignation saying that it was “obvious” that she can no longer “fulfill her duties.”

In response the former Speaker of the House, Representative Nancy Pelosi, 83, who like Ms. Feinstein is a wealthy San Franciscan, suggested that a man in Ms. Feinstein’s position would not have faced the same scrutiny and that she “deserves the respect to get well and be back on duty.”

According to Mr. Coleman, these calls for resignation look more like political jockeying ahead of what is expected to be a blockbuster Senate primary in California than serious demands from party leadership.

For Mr. Khanna, Ms. Feinstein’s resignation could be a boon to the prospects for his favorite candidate in the race to replace Ms. Feinstein, Representative Barbara Lee, 76.

That’s because Governor Newsom has promised to appoint a black woman as Senator if given the chance and Ms. Lee’s name is probably near the top of that list.

Ms. Lee herself has taken a less aggressive approach in her positioning, only announcing her candidacy for Ms. Feinstein’s spot after the senator announced she would not seek re-election, even as other Democrats announced earlier.

Still, for Ms. Lee becoming the incumbent in a race that could become the most expensive Senate race ever could boost her prospects over her leading competitors, Representatives Adam Schiff, 62, and Katie Porter, 49.

The behind the scenes intrigue into the potential impact of a replacement on the 2024 race is beside the point, or at least premature, because it’s clear that Ms. Feinstein has no intention of resigning, at least for now. The senator and her staff are now practiced at resisting questions concerning her health.

For the last year, she has been the object of a concerted whisper campaign to step down with associates leaking the press that she is suffering from dementia and no longer able to perform her duties.

A vestige of the Senate’s more collegial past, she was savaged by the left for not being sufficiently antagonistic to conservative Supreme Court nominees, Justices Brett Kavanagh and Amy Coney Barrett. She announced earlier this year that she would not seek reelection, but that has not been enough for the progressive left, who want her gone immediately.

One anonymous California Democrat told Politico, concerning the issue, that Ms. Feinstein “is not going to respond to pressure” and that “Ro Khanna has no influence on her whatsoever.”

In Mr. Coleman’s opinion, members of the Senate are unlikely to make any public calls for resignation at this time, because the ideal scenario is Ms. Feinstein’s return to the committee, an outcome that’s still possible.

However, if the situation persists, more judicial nominees are unable to be confirmed, and Ms. Feinstein still has no timeline for returning to the Senate, there might be calls for her resignation from party members with more sway than Mr. Khanna later in the spring or in early summer.

It is unclear why Ms. Feinstein is so unwilling to step down. Her refusal hearkens back to a comment Senator Hollings made in 2001 about Senator Thurmond, then 98, whom he said was using the Senate as “a nursing home.”

It’s “sad because the poor fellow doesn’t have any place to go,” he said.