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Some grumbled, they made grave expressions of concern, and they called for answers. But, so far at least, Republican in the Senate have stopped short of calling for an independent investigation into Russian meddling in U.S. politics after President Donald Trump’s abrupt firing of FBI Director James Comey Tuesday.

Democrats, who question whether Comey’s termination was an attempt to quash the FBI’s probe into potential collusion between the Trump campaign and Russian agents, renewed their call for a special prosecutor or independent 9/11-style commission.

But other than a handful of Republicans in the House, however, the GOP was largely united against the idea.

Notably, the Senate’s top leaders were especially resistant.

"Today, we'll no doubt hear calls for a new investigation, which could only serve to impede the current work being done," Senate Majority Leader Mitch McConnell said on the Senate floor.

"The FBI is about more than just one investigation," Senator John Cornyn (R-TX), the majority whip, said.

He dismissed Democratic demands that the Justice Department appoint a special prosecutor before the next FBI director is confirmed as a “ridiculous position.”

Sen. Richard Burr (R-NC), chairman of the Senate Intelligence Committee, turned heads by saying he was "troubled" by the timing of Comey’s ouster.

But Burr, who advised the Trump transition team and is leading the chamber’s parallel investigation into the Russian meddling, also pushed back on calls for an independent investigation.

"To suggest that I’d be for a special prosecutor would say I don’t think I can do my job, which is to lead an investigation. So I’m not in favor of a special prosecutor because I think the committee can carry out its responsibility, can come to a conclusion," he said at a press conference.

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Several of Trump’s most outspoken GOP critics fell into the party line, saying an outside investigation was unwarranted or premature — even as they criticized Trump for the manner in which he removed Comey.

"The President did not fire the entire FBI; he fired the director," Sen. Susan Collins (R-ME), one of her caucus’ most moderate members, said in a statement. "I have every confidence that the FBI will continue to pursue its investigation."

"This is a counterintelligence investigation, we don’t have special prosecutors for a counterintelligence investigation," Sen. Lindsey Graham (R-SC) told NBC News’ Kristen Welker Wednesday. "If it became a criminal investigation, then we’d have a discussion."

The one exception in the upper chamber was Sen. John McCain (R-AZ), who has long called for a special committee in the Senate to look into the Russia issue.

"The president's decision to remove the FBI Director only confirms the need and the urgency of such a committee," McCain said in a statement. Still, his recommendation fell short of Democratic demands for an independent prosecutor chosen by a career Justice official rather than Trump’s appointees.

The firing was the latest controversy dumped into the laps of Senate Republicans, who will now have to navigate a contentious confirmation process for Comey’s replacement, who has yet to be named, in addition to their other duties.

Democrats cannot filibuster the appointment, thanks to a change in Senate rules executed by former Democratic Sen. Harry Reid when he ran the chamber in 2013. But Republicans can only afford two defections from their narrow 52-seat majority if every Democrat withholds support.

While Democrats have yet to lay out their strategy for the confirmation fight, Trump’s nominee is likely to face plenty of opposition.

"Frankly, we should hold off on the FBI director until we get this special prosecutor," said Sen. Mark Warner (D-VA), a moderate up for reelection this year who is his party's top-ranking member on the Intelligence Committee.

Politically, Democrats feel confident fighting on this issue. A Democratic super PAC, American Bridge, started re-running digital ads asking voters to press two vulnerable Republican senators — Dean Heller (R-NV) and Sen. Jeff Flake (R-AZ) — to call for an outside prosecutor.

"I just don't know why this happened now. I'm having trouble with it still," Flake, one of Trump’s most vocal Republican antagonists, said Wednesday of Comey’s removal. "So with regard to a special prosecutor, I'm looking to see how that would impact the senate investigation that's going on. I have confidence in the Senate Intelligence Committee."

Senate Committee on Intelligence members Sen. Mark Warner, Sen. Dianne Feinstein, Sen. Dan Coats, and Chairman Richard Burr confer before hearing a testimony on Capitol Hill on Sept. 27, 2016 in Washington, D.C. Chip Somodevilla / Getty Images

Fifty-six percent of American support a special prosecutor for the Russian probe, according to a March Politico/Morning Consult poll, including a majority of independents.

Republicans have gotten used to navigating questions about Trump's tweets or controversial remarks. But the firing of an FBI director overseeing an active investigation into allies of the president pushed the White House into uncharted waters.

"There is no question we are in a very volatile, sensitive and fragile time in this nation," Sen. Tim Scott (R-SC) told NBC News, adding that the timing of Comey’s firing "raises my attention."

Still, Scott said he wasn’t sure if an independent prosecutor is warranted.

"I don't have any recommendations," Sen. Bob Corker (R-TN), who chairs the Senate Foreign Relations Committee, said when asked about an independent prosecutor.

Sen. Johnny Isakson (R-GA) was relaxed as he fielded reporters' questions about the previous 24 hours. "That's the president's person to hire and the president’s person to fire, so I mean," Isakson said, trailing off. Asked how he felt personally about the move, he replied: "This is not an emotional business."

Some White House allies were outright enthusiastic about the move. "President Trump acted decisively and within his authority, and I stand behind him," Senator David Perdue (R-GA) said in a statement.

Two of the three Russian investigations have now been contaminated by politics, raising doubts about their capabilities to find answers that the public would broadly consider credible.

The House Intelligence Committee's probe was knocked off course after the panel’s GOP chairman was forced to recuse himself. And now, Comey’s firing has put a cloud over the FBI’s probe. Attorney General Jeff Sessions had previously recused himself as well and Democrats argued on Wednesday that his role in removing Comey violated that pledge.

That leaves the Senate Intelligence Committee, which has so far operated in a bipartisan fashion without major public infighting. But Democrats looking for GOP help in launching a new outside investigation should look elsewhere. There’s little sign the party has moved closer to their position.