Sen. Dianne Feinstein walks to the Senate Chambers during a series of the votes at the US Capitol Building on February 13 in Washington, DC.
CNN  — 

Republicans on Tuesday formally blocked a request from Senate Majority Leader Chuck Schumer to temporarily replace Sen. Dianne Feinstein on the Judiciary Committee, something Democrats hoped to do in order to advance stalled judicial nominations.

Senate Democrats are seeking to temporarily replace Feinstein on the powerful panel that processes judicial nominees as the California Democrat remains absent, recovering from shingles.

Senate Republicans, however, have made clear that they have been prepared to block Democratic efforts to replace Feinstein on the committee, ratcheting up pressure on the 89-year-old California Democrat to resign or return quickly.

Feinstein’s return date is still unclear and she asked just last week to be “temporarily” replaced on the committee as she recovers.

Schumer introduced his motion on Tuesday by talking about his friendship with Feinstein, and highlighting her accomplishments.

“Today, I am acting not just as Leader but as Dianne’s friend, in honoring her wishes, until she returns to the Senate,” Schumer said.

GOP Sen. Lindsey Graham, the top Republican on the Senate Judiciary Committee, objected to Schumer’s request, though he also praised the California Democrat. He argued that Schumer’s move is to get more judges confirmed.

“She’s a dear friend and we hope for her speedy recovery and return back to the Senate. With all due respect, my colleague, Senator Schumer, this is about a handful of judges that you can’t get the votes for,” Graham said.

Democrats could still force a vote to replace the Feinstein, but that would require the support of 10 Republicans and it’s unlikely they would use a lot of valuable floor time for something with little chance of success.

Feinstein, who has already announced she’s not seeking reelection, initially said she expected to return to Washington “by the end of the March work period,” but that her return got “delayed due to continued complications related to my diagnosis.”

She recently said she plans to return “as soon as possible once my medical team advises that it’s safe for me to travel.”

Cardin told CNN Tuesday he had discussed with Schumer being the temporary replacement on the committee but that he had not discussed the decision with Feinstein.

The Maryland Democrat said he and Feinstein have not spoken since she’s been out of the Senate and that it is his understanding that this is only a temporary move until she returns.

“I recognize the importance of the numbers on the committee, and this way we can be able to conduct business. I look at this as a way of dealing with a current situation,” Cardin said.

Democrats would need 60 votes to replace Feinstein on the panel, but senior Republicans in leadership and on the committee made clear Monday that they would not give them the votes to do that. If Feinstein does not return soon, at least 12 nominees, or possibly even more, could be stalled.

If Democrats are unable to replace Feinstein or if she does not return to Washington soon, they could see key agenda items thwarted – both on the committee and on the Senate floor.

Asked if the California Democrat should consider resigning if she can’t return by May, Schumer responded that he’s “hopeful” she will return “very soon.”

“Look, I spoke to Senator Feinstein just a few days ago and she and I are both very hopeful that she will return very soon,” Schumer said at his weekly policy press conference in the US Capitol.

Feinstein announced in February that she would not run for reelection, and a number of Democrats have already launched campaigns for her seat in 2024 in what is shaping up to be a competitive primary.

Many congressional Democrats have remained largely supportive of her decision to remain in office while absent from the Capitol as she recovers from shingles.

But Feinstein has faced calls to resign from two House Democrats – and if Democrats are not able to replace her on the committee, that number could start to grow.

Senate Judiciary Chairman Dick Durbin recently acknowledged to CNN that Feinstein’s absence had slowed down the party’s push to confirm nominees. But Durbin has stopped short of calling on Feinstein to resign, saying he hopes that Republicans will help to temporarily replace her on the committee and recognize that “the rain can fall on both sides of the road.”

Asked if her absence has longer ramifications for the Democrats’ ability to confirm nominees, the Illinois Democrat said, “Yes, of course it does,” pointing to the long process of getting nominees scheduled for votes during precious floor time.

Republican Sen. John Cornyn, a senior member on the Judiciary Committee and close adviser to McConnell, told CNN that he opposes the effort to replace Feinstein on the panel.

“I don’t think Republicans can or should help President Biden’s most controversial nominees,” the Texas Republican said. “I support having Sen. Feinstein come back as soon as she can. But this effort to confirm controversial and in many instances largely unqualified nominees, I don’t think you can expect any Republican cooperation.”

This story has been updated with additional information.

CNN’s Manu Raju and Alayna Treene contributed.