Robert S. Mueller III, the special counsel probing Russian interference in the 2016 election, departs Capitol Hill in Washington in June. (Andrew Harnik/AP)

Republican senators who worked swiftly last summer to help write legislation protecting special counsel Robert S. Mueller III now are showing little urgency to get those measures passed.

The legislation, which would allow a panel of federal judges to review orders to fire the special counsel, was intended to prevent President Trump from pushing out Mueller before he completes his investigation of Russian meddling in the 2016 election.

But two different bipartisan proposals have been mired in negotiations for months. And despite continuing signs from the president that he is unhappy with Mueller's investigation — which prompted the initial call for the legislation — Republicans appear to be losing their resolve to act.

"We're still having the discussion," Sen. Thom Tillis (R-N.C.), the co-author of one of the bills, said this week. "It's not driven by any current events."

Sen. Lindsey O. Graham (R-S.C.), another co-author of one of the bills, said, "I don't really know," when asked the status of negotiations.

The lack of action has prompted some Democrats to accuse Republicans of intentionally drawing out passage of the legislation.

"There is a sense that the wagons have been circled," said Sen. Richard Blumenthal (D-Conn.), a member of the Senate Judiciary Committee and co-sponsor of one of the two bills. Blumenthal said his GOP colleagues are under "political pressure" not to cross the president on Russia.

"The question is really whether our Republican colleagues have a sense of emergency that I think befits our present situation," Blumenthal said.

There is not much left to negotiate. Both Democrats and Republicans say the main sticking point between the two bills is a dispute over whether a three-judge review of a special counsel's termination should occur automatically or at the special counsel's request.

But should senators produce a compromise bill, the next hurdle is significant: convincing skeptical Republicans that it is constitutional for a three-judge panel to review a president's termination order, when people in the executive branch serve at the pleasure of the president.

"I've never been convinced they're constitutional," said Sen. John Neely Kennedy (R-La.), a member of the Judiciary committee.

[Trump team’s meeting with Mueller’s office poised to ratchet up tensions]

On the other side of the Capitol, House Republicans have not drafted parallel legislation, many of them instead joining forcefully with Trump in criticizing Mueller's investigation. In particular, they have called for a separate independent investigation of political bias within the FBI, following revelations of texts between bureau officials disparaging Trump.

Graham, Tillis, Cory Booker (D-N.J.) and Christopher A. Coons (D-Del.) wrote their bills over the summer to protect Mueller after Trump hinted that he might fire Attorney General Jeff Sessions as a way of reorganizing the Justice Department. At the time, Trump was furious that Sessions, a Trump loyalist, had recused himself from campaign-related matters at the department, leaving oversight of Mueller's probe to Deputy Attorney General Rod J. Rosenstein.

Installing a new, loyal attorney general with direct oversight of the investigation could make it easier for Trump to force Mueller's dismissal.

If anything, Trump's invective against Mueller has escalated since then.

Earlier this month, after former national security adviser Michael Flynn pleaded guilty to lying to the FBI about his contacts with former Russian Ambassador to the United States Sergey Kislyak, Trump launched a Twitter storm criticizing the bureau and its previous director, James B. Comey.

[‘I never asked Comey to stop investigating Flynn’: Trump goes on tweetstorm about the FBI]

This week, an attorney for Trump's presidential transition joined the fray, arguing that Mueller improperly obtained the Trump transition team's emails from the General Services Administration rather than from the transition team directly.

The lack of resolution has some Democrats convinced that Republicans are holding off to give Trump wiggle room to fire Mueller if the probe gets too close for comfort to the Oval Office.

In a floor speech Wednesday, Senate Intelligence Committee Vice Chairman Mark R. Warner (D-Va.) accused House Republicans calling for Mueller's ouster of participating in a "seemingly coordinated" campaign to promote "baseless accusations" against Mueller's character and professionalism.

After his remarks, Warner stopped short of charging the White House with actively coordinating the campaign when asked by reporters — and also demurred when asked if Senate Republicans were complicit by not doing anything to protect Mueller's probe.

"It's hard for me to imagine that they wouldn't be troubled by what appears to be a coordinated effort to undermine Mueller in many ways — more broadly, even, the FBI," Warner said, attributing the Senate GOP's inaction to lawmakers' preoccupation with the tax bill that passed along near-party lines Wednesday.

The White House again pushed back on the rumors of a possible firing of Mueller Wednesday evening.

"For five months or more the White House has persistently and emphatically stated there is no consideration of firing the Special Counsel and the White House willingly affirms yet again, as it has every day this week, there is no consideration being given to the termination of the Special Counsel," Ty Cobb, a White House lawyer overseeing the Russia investigation, said in a statement.

Tillis has said repeatedly over the last few weeks that he wants to strike a deal on legislation to protect the special counsel. But he also noted Trump's statement over the weekend that he has no plans to fire Mueller — and said he believes the president.

Graham echoed that sentiment — and also voiced support for a growing effort within the Senate GOP to shift the discussion to the need for separate investigations into bias at the FBI as well as the Justice Department's handling of the Hillary Clinton email probe, and a 2010 decision to let Russia assume a significant stake in the U.S. uranium market

"I take the president at his word, he has no intention to fire Mueller," Graham said.

Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) said he is waiting to see what negotiators come up with before he even considers putting a bill through the legislative process.

"I suspect there are some Republicans that may not want to pass [the bill]," said Sen. Dianne Feinstein (D-Calif.), the leading Democrat on the Judiciary Committee, though she warned that "nothing would be worse for the GOP" than if Trump fired Mueller.

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