Legislation protecting special counsel Robert MuellerRobert (Bob) MuellerBarr taps attorney investigating Russia probe origins as special counsel CNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting MORE was blocked on Wednesday for a second time in the past month.

Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeBiden eyeing Cindy McCain for UK ambassador position: report Profiles in cowardice: Trump's Senate enablers McSally concedes Arizona Senate race MORE (R-Ariz.), joined by Sens. Christopher CoonsChris Andrew CoonsThe Hill's Morning Report - Presented by Mastercard - GOP angst in Georgia; confirmation fight looms Overnight Health Care: Moderna to apply for emergency use authorization for COVID-19 vaccine candidate | Hospitals brace for COVID-19 surge | US more than doubles highest number of monthly COVID-19 cases Bipartisan Senate group holding coronavirus relief talks amid stalemate MORE (D-Del.) and Cory BookerCory BookerBiden budget pick sparks battle with GOP Senate Policy center calls for new lawmakers to make diverse hires Dangerously fast slaughter speeds are putting animals, people at greater risk during COVID-19 crisis MORE (D-N.J.), tried to get consent to schedule the long-stalled legislation for a vote. 

Flake questioned why his colleagues weren't "up in arms" after a string of tweets from President TrumpDonald John TrumpTrump alludes to possible 2024 run in White House remarks Trump threatens to veto defense bill over tech liability shield Tiger King's attorney believes they're close to getting pardon from Trump MORE bashing Mueller's investigation into Russian interference in the 2016 presidential election.

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"With the president tweeting on a regular basis, a daily basis, that the special counsel is conflicted, that he is leading so-called 12 angry Democrats and demeaning and ridiculing him in every way, to be so sanguine about the chances of him being fired is folly for us," Flake said.

Trump in a tweet hours before Flake's request blasted Mueller's probe into Russian election interference and possible collusion between the president's campaign and Moscow as the "angry Mueller gang of Dems" and exclaimed that it is "our Joseph McCarthy era."

But GOP Sen. Mike LeeMichael (Mike) Shumway LeeGrassley returns to Capitol after having coronavirus McConnell halts in-person Republican lunches amid COVID-19 surge Loeffler isolating after possible COVID-19 infection MORE (Utah) objected to voting on the legislation, arguing the bill had constitutional issues.

"As Justice Scalia explains, we cannot convert an office like this one ... without creating a de facto fourth branch of government fundamentally undermining the principles of the separation of powers that is so core to our liberty," Lee said.

Flake pledged that they would come back to the Senate floor to try to set up the bill for a vote again.

Under the upper chamber's rules, senators can go to the floor to request a vote or passage of any bill or nomination. But any one senator can block their requests. 

The floor drama comes after Senate Majority Whip John CornynJohn CornynMcCaskill: 'Hypocrisy' for GOP to target Biden nominee's tweets after Trump Former Senate hopeful auctioning off Harley-Davidson featured prominently in her campaign ads The Hill's Morning Report - Presented by Mastercard - GOP angst in Georgia; confirmation fight looms MORE (R-Texas) said Republican leadership was measuring support for the bill to try resolve a standoff with Flake, who is voting against judicial nominees until the Mueller protection bill gets a vote. 

"We're whipping that to see where people are. I think the leader needs that information to decide how to manage all the competing demands on our time," Cornyn said when asked about discussions within the Republican caucus about the legislation.

But there is still fierce opposition to the bill within the GOP caucus, and Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellPressure builds for coronavirus relief with no clear path to deal Top GOP senator warns government funding deal unlikely this week Criminal justice groups offer support for Durbin amid fight for Judiciary spot MORE (R-Ky.) called it a “solution in search of a problem” on Tuesday. 

The president has stepped up his Twitter attacks on Mueller's probe in recent days amid several new revelations, including the special counsel's charge that former Trump campaign chairman Paul ManafortPaul John Manafort3 take-aways from the Michael Flynn pardon Flynn spurs questions of who Trump might pardon next On The Money: Initial jobless claims rise for 2nd week | Dow dips below 30K | Mnuchin draws fire for COVID-19 relief move | Manhattan DA appeals dismissal of Manafort charges MORE had violated his plea agreement. 

New reports emerged on Tuesday that Manafort's attorney had been sharing information with attorneys for Trump on his former campaign aide's cooperation with the Mueller probe. 

Trump after the midterm elections forced Attorney General Jeff SessionsJefferson (Jeff) Beauregard SessionsTime to bring federal employees home for every holiday Alabama zeroes in on Richard Shelby's future Tuberville incorrectly says Gore was president-elect in 2000 MORE to resign and named Matthew Whitaker, Sessions's chief of staff, as acting attorney general. Whitaker, who has criticized the Mueller probe, is now overseeing it in place of Deputy Attorney General Rod RosensteinRod RosensteinTrump turns his ire toward Cabinet members Ex-deputy attorney general says Justice Dept. 'will ignore' Trump's threats against political rivals The Hill's Morning Report - Sponsored by Facebook - Trump's erratic tweets upend stimulus talks; COVID-19 spreads in White House MORE

The Senate Judiciary Committee passed legislation that would protect Mueller, or any other special counsel, in the event he is fired, but the bill has stalled amid opposition from GOP leadership.

The bill would codify Justice Department regulations that say only a senior department official could fire Mueller or another special counsel.

It would give a special counsel an "expedited review" of their firing. If a court determines that it wasn't for "good cause," the special counsel would be reinstated.

Updated at 12:59 p.m.