Legislation protecting special counsel Robert MuellerRobert (Bob) Swan MuellerTrump calls for probe of Obama book deal Democrats express private disappointment with Mueller testimony Kellyanne Conway: 'I'd like to know' if Mueller read his own report MORE was blocked on Wednesday for a second time in the past month.

Sen. Jeff FlakeJeffrey (Jeff) Lane FlakeArpaio considering running for former sheriff job after Trump pardon Overnight Energy: Warren edges past Sanders in poll of climate-focused voters | Carbon tax shows new signs of life | Greens fuming at Trump plans for development at Bears Ears monument Carbon tax shows new signs of life in Congress MORE (R-Ariz.), joined by Sens. Christopher CoonsChristopher (Chris) Andrew CoonsThe United States broken patent system is getting worse Biden faces scrutiny for his age from other Democrats Democrats press FBI for details on Kavanaugh investigation MORE (D-Del.) and Cory BookerCory Anthony BookerThe Hill's Campaign Report: Battle for Senate begins to take shape Steve King to Gillibrand: Odds of me resigning same as yours of winning presidential nomination We need a climate plan for agriculture 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 watching 'very closely' as Portland braces for dueling protests WaPo calls Trump admin 'another threat' to endangered species Are Democrats turning Trump-like? MORE bashing Mueller's investigation into Russian interference in the 2016 presidential election.

ADVERTISEMENT

"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 LeeMcConnell, allies lean into Twitter, media 'war' Conservatives buck Trump over worries of 'socialist' drug pricing Criminal justice reform should extend to student financial aid 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 CornynThe Hill's Campaign Report: Battle for Senate begins to take shape The Hill's Morning Report — Trump and the new Israel-'squad' controversy O'Rourke says he will not 'in any scenario' run for Senate 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 McConnellAre Democrats turning Trump-like? House Democrat calls for gun control: Cities can ban plastic straws but 'we can't ban assault weapons?' Churches are arming and training congregants in response to mass shootings: report 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 ManafortTrial of ex-Obama White House counsel suddenly postponed Top Mueller probe prosecutor to join Georgetown Law as lecturer DOJ releases notes from official Bruce Ohr's Russia probe interviews 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 SessionsLewandowski says he's 'happy' to testify before House panel The Hill's Morning Report — Trump and the new Israel-'squad' controversy Nadler subpoenas Lewandowski, former White House official for testimony 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 RosensteinWhy the presumption of innocence doesn't apply to Trump McCabe sues FBI, DOJ, blames Trump for his firing Rosenstein: Trump should focus on preventing people from 'becoming violent white supremacists' 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.