The three Democratic presidential candidates who sit on the Senate Judicial Committee sparred with Attorney General William Barr on Wednesday over his controversial handling of Special Counsel Robert Mueller’s Russia investigation report.

Following the much-anticipated hearing, two of them – Sens. Kamala Harris of California and Sen. Cory Booker of New Jersey - joined a growing number of Democratic White House hopefuls calling on Barr to resign.

TENSIONS FLARE AT BARR HEARING ON CAPITOL HILL

Harris – in her grilling about the attorney general’s decision not to say President Donald Trump committed obstruction of justice – accused Barr of being “biased in this situation” and of “having a conflict of interest."

Harris - a former California attorney general and San Francisco district attorney - asked Barr whether he would “agree to consult career DOJ (Department of Justice) ethics officials about whether your recusal from the 14 investigations that have been discussed by my colleagues is necessary.”

Barr - who has been accused by Democrats of defending the president as he unveiled Mueller’s report - said that he’d already consulted with DOJ ethics officials and he asked the senator “on what basis” he should recuse himself from the investigations.

“Conflict of interest, clear conflict of interest,” Harris shot back.

“What’s my conflict of interest?” Barr asked.

“I think the American public has seen quite well that you are biased in this situation and you’ve not been objective and that would arguably be the conflict of interest,” Harris responded.

In another tense exchange, Harris zeroed in on Barr’s earlier statement that he consulted constantly about Mueller’s report with Deputy Attorney General Rod Rosenstein.

Harris emphasized that Rosenstein was a key witness in the 2017 firing of then-FBI Director James Comey, which helped spark Mueller’s investigation.

“Did you consult with DOJ ethics officials before you enlisted Rod Rosenstein to participate in a charging decision for an investigation that subject of which he’s also a witness?

Barr responded that “my understanding was that he was cleared already to participate” and added that “this seems to be a flip flop.”

Harris shot back, saying “sir, the flip flop is that you’re not answering the questions.”

She also pointed to Barr’s initial March 24 summary of Mueller’s report, where he wrote that he and Rosenstein, after reviewing Mueller’s evidence, concluded that there was not enough evidence to establish that the president had committed obstruction of justice.

Harris asked Barr whether he personally reviewed all of the underlying evidence in reaching his conclusion.

He said no and explained that “we accepted the statements in the report as factual record… We accepted it as accurate.”

Harris ended the line of questioning by saying, “I think you’ve made it clear, sir, that you’ve not looked at the evidence and we can move on.”

After the hearing, Harris told reporters that Barr needs to resign, charging that the attorney general “lacks all credibility and has, I think, compromised the American public's ability to believe that he is a purveyor of justice."

Booker also tweeted that Barr must go.

“Attorney General Barr answers to the American people—not to President Trump—and over the past 24 hours it’s become clear that he lied to us and mishandled the Mueller Report. He needs to step down,” Booker urged.

Earlier, during his questioning of the attorney general, Booker charged that Barr’s actions undermined “your own credibility as an independent actor… We are going into an area where you seem to not even be willing to be in the least bit critical in your summarizations. I believe that calls in your credibility.”

“I fear that you are adding normalcy to a point where we should be sounding alarms as opposed to saying there’s nothing to see here,” Booker said.

Booker argued that “we right now have a new normal in our country. We have a document that shows folks over 200 connections between a presidential campaign and a foreign adversary sharing information that would be illegal if you did it with a super PAC.

Barr shot back, asking “what information was shared?”

Booker responded that “polling data was shared, sir. It’s in the report, I can cite you the page.”

He also claimed that the attorney general’s “willingness to seem to brush over this and use words like the American people should be ‘grateful’ of what’s in this report, nobody should be grateful.”

The third Democratic presidential candidate on the committee, Sen. Amy Klobuchar of Minnesota, topped her questioning by asking Barr to support the ‘Secure Elections Act,’ a bill she and Republican Sen. James Lankford of Oklahoma introduced that also has the support of Harris and Sen. Lindsey Graham of South Carolina, the Republican chair of the Judiciary Committee.

The bipartisan measure, which would strengthen election cybersecurity in America and protect against interference by Russia and other hostile countries in future elections, would require backup paper ballots.

"What I would like to know from you as our nation's chief law enforcement officer, if you will work with us to get this bill done," Klobuchar asked. "Otherwise we have no clout to get backup paper ballots if something goes wrong in this election."

Barr responded that "I will work with you to enhance the security of our election, and I will take a look at what you are proposing. I'm not familiar with it.”

She also elicited a commitment from Barr to have the FBI provide a briefing to all senators on recent Russian tampering in U.S. elections.

Klobuchar, an attorney, sparred with Barr over whether the president’s specific comments would pass muster as obstruction of justice.

Barr answered no, adding that “the government has to prove things beyond a reasonable doubt and as the report shows, theirs is ample evidence on the other side of the ledger that would prevent the government from establishing that” there was obstruction of justice by the president.

Klobuchar responded, “I look at the totality of the evidence and when you look at it, it is a pattern.”

Prior to the hearing, a number of Democratic presidential candidates called on Barr to step down.

Sen. Elizabeth Warren of Massachusetts tweeted that the “Attorney General does not swear an oath of loyalty to any one individual. The AG swears an oath of loyalty to the Constitution of the United States. Barr has made clear that he doesn't swear his loyalty that way & that disqualifies him from being AG. He should resign.”

Joining her was another 2020 rival, Sen. Kirsten Gillibrand of New York, who tweeted that “Barr needs to resign. Today, he's proven once again that he's more interested in protecting the president than working for the American people. We can't trust him to tell the truth, and these embarrassing displays of propaganda have to stop.”

And on the eve of the hearing, former San Antonio mayor and former Housing and Urban Development Secretary Julian Castro argued that “Barr willfully misled the American people to cover up attempted crimes by Donald Trump. He should resign his position or face an impeachment inquiry immediately.”

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Meantime, former Texas Rep. Beto O'Rourke said Barr "has failed in his responsibility to our country."

And, on Wednesday evening, former Vice President Joe Biden was asked at an Iowa campaign stop if Barr should resign. He responded, "I think he’s lost the confidence of the American people, I think he should."

Fox News' Allie Raffa contributed to this report.