drnadig/iStockBy TRISH TURNER, ABC News

(WASHINGTON) -- A bitter partisan fight in the Senate Judiciary Committee on Thursday forced its GOP chairman, Lindsey Graham, to delay a vote that would give him unilateral subpoena power in a GOP-led probe of the counterintelligence investigation that led to the appointment of special counsel Robert Mueller.

The move for subpoena authority -- which Graham predicted would be approved in a party-line vote next week -- would allow him to compel the appearance of more than 50 witnesses, the majority of whom served in the Obama administration. One currently works for former Vice President Joe Biden's presidential campaign.

Democrats condemned the Republican move as raw politics in service of President Donald Trump's reelection.

Graham, a top Trump ally, noted that he supported Democrats in their effort to shield Mueller from being fired and it was time they back him in return.

He claimed he was just doing what Democrats had done years earlier when they dug into alleged Bush-era detainee torture, giving the panel's chairman the same subpoena authority.

But Democrats fired back that their probe was a years’ long effort not timed before an election and which, at times, had bipartisan support.

Ranking Democrat Dianne Feinstein, a 26-year member of the panel, charged Thursday that Graham’s motion was merely "an unbridled, dragnet authority to conduct politically-motivated investigations."

As the verbal sparring reached a crescendo, a clearly-exasperated Sen. Ben Sasse, R-Neb., interrupted his colleagues, accusing all of them of showboating for the media.

"It’s bull**** the way that people grandstand for cameras around here," Sasse said. "The Senate doesn't work ... 90 percent of our committees is about people trolling for sound bites."

The moment seemed to reduce the tension, with Graham eventually agreeing to delay the subpoena vote by a week to permit further conversations among members, though the partisan outcome seemed assured.

Still, Sen. Kamala Harris, D-Calif., chastised her GOP colleagues for ignoring what was happening just outside their own building, as protestors of racial injustice there and around the country demanded policing reforms in the wake of George Floyd’s death.

“I would dare say the conversation we are having today is irrelevant to what is happening on the streets of America,” Harris said. “Today we are looking at people in pain, people by the thousands of every race, age and geographic location, shouting for justice in America. Yet this committee doth protest too much, as Shakespeare might say, on an issue that is not relevant to the people and the pain that America is feeling today.”

Graham cited his plan to hold a hearing on June 16 related to Floyd’s death and potential policing reforms in America.

He promised to allow a vote next week on a Harris amendment that would not allow any subpoena motion by Graham to be approved, as the senator explained, "until this committee has conducted a thorough investigation and held a hearing to examine the conduct of Attorney General Barr on June 1, 2020, when he reportedly ordered federal law enforcement personnel to remove peaceful protestors who were engaged in constitutionally protected activity."

It was unclear how that vote on the Harris amendment might fare next week. Republicans who spoke on Thursday were supportive of Graham's action which the chairman has said would result in a report by October -- just ahead of Election Day.

"I support the investigation into this rogue FBI counterintelligence investigation known as Crossfire Hurricane," said committee Republican John Cornyn of Texas.

Republicans, fueled by an angry, frustrated Trump, who has claimed without evidence that he was personally spied on and was a victim of a '"coup attempt" by Obama administration holdovers, have launched multi-pronged investigations, including one that touches his Democratic opponent -- Biden -- and his son, Hunter, who was on the board of a Ukrainian energy company.

Over in the Senate Homeland Committee Thursday, Republicans voted along party lines to approve unilateral subpoena power for its chairman to dig into how law enforcement investigated the Trump presidential transition.

"It is our job to investigate and provide the American people a complete accounting of what happened during the last transition," said Chairman Ron Johnson, R-Wisc., noting that he hoped witnesses would cooperate and that subpoenas would not ultimately be necessary.

"With all of the other pressing matters facing our country at this extremely troubling time, it’s difficult to understand why you have chosen to make this a priority for the committee’s time and resources now but did not pursue it at any other time during your chairmanship," said Sen. Gary Peters, the top Democrat on the panel, who charged Johnson with advancing "a fishing expedition" with a threat of some 36 subpoenas.

Rebutting that criticism, Johnson assured members, "The vast majority of my time and my staff’s time" would be devoted to pressing issues like COVID-19, policing concerns and the protests convulsing the country in reaction to Floyd’s death.

The Graham-led Trump-Russia probe was sparked by a Department of Justice watchdog's finding of multiple problems with the way the FBI obtained secret surveillance warrants for surveillance of former Trump campaign adviser Carter Page. But no Republican publicly acknowledged Thursday that the watchdog also found that the Mueller probe "was opened for an authorized investigative purpose and with sufficient factual predication."

"I want to know how you could renew a warrant on two different occasions months apart," Graham argued, referring to warrants renewed to surveil Page, adding, "Isn't it our job to try to find out what happened?"

Despite the raw rhetoric, Graham did agree with Democrats that a former Mueller investigator could be called as a witness.

"I'm not averse to someone from the Mueller team coming and telling the committee what they did and how they did it," Graham said of a request by Feinstein, with the chairman personally suggesting lead Mueller prosecutor Andrew Weismann. "I am very open to getting somebody from the Mueller team over here during the course of our inquiry."

On Wednesday, the committee held its first hearing in the probe with a voluntary appearance by former Deputy Attorney General Rod Rosenstein, who supervised the Mueller investigation after then-Attorney General Jeff Sessions recused himself.

Repeatedly, Republicans probed him about the Page warrants, which he acknowledged were problematic, but he was adamant that the investigation was legitimate and not improperly founded.

"I do not consider the investigation to be corrupt," Rosenstein said in the hearing. "But I certainly understand the president’s frustration given the outcome which was in face there was no evidence of conspiracy between Trump campaign advisors and Russians.”

Graham on Thursday said he knew Democrats would never agree with him about the current probe and explained that's why he was seeking unilateral subpoena authority so early in the investigation. But he acknowledged that the disagreement had become personal, despite years-long, bipartisan friendships, as Democrats warned that committee comity would be destroyed if the chairman continued forward.

"It's not lost on me what you think of me," Graham said. "It's clear to me that you're' not going to help me."

"Ya'll could care less, and that really says a lot about this committee," Graham continued. "We're going to go wherever the evidence takes us. And now we're trying to answer some basic questions."

"Given what we're about to do now, this is the Senate at its worst," declared Sen. Patrick Leahy, D-Vt., the chamber's longest serving Democrat.

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