Barr was put on the defensive hours ahead of his testimony Wednesday before the Senate Judiciary Committee with the disclosure that Mueller had written a letter objecting that the attorney general misrepresented his report on Russia interference in the 2016 election.

“It was my decision how and when to make that public, not Bob Mueller’s,” Barr said of a summary he released in late March. Barr said questions about Mueller’s concerns are “mind-bendingly bizarre” because he always planned to issue the report after redacting certain sensitive details.

He testified that he felt he needed to “notify the people as to the bottom-line conclusion” before a redacted version of Mueller’s 448-page report could be released. When Mueller argued that his summaries should be made public quickly, Barr said, “I told Bob that I was not interested in putting out summaries and I was not interested in putting out the report piecemeal.”

But Democrats on the committee — and beyond — challenged Barr’s explanation of his differences with Mueller. Democratic leader Chuck Schumer said on the Senate floor that the disclosure raises “damning questions about his impartiality and about his fitness.”

Mueller contacted Barr to express his displeasure after the attorney general issued his four-page letter in March characterizing the main findings of Mueller’s investigation.

“The summary letter the department sent to Congress and released to the public late in the afternoon of March 24 did not fully capture the context, nature, and substance of this office’s work and conclusions,” Mueller wrote.

Mueller wrote that Barr’s letter created “public confusion” about important parts of the results of the special counsel’s 22-month probe. “This threatens to undermine a central purpose for which the Department appointed the special counsel: to assure full public confidence in the outcome of the investigations,” Mueller wrote in the letter reported Tuesday evening by the Washington Post.

Barr told the Senate panel near the close of the hearing that “the letter is a bit snitty, and I think it was probably written by one of his staff.”

While the Justice Department portrayed Barr’s differences with Mueller as a friendly exchange of opinion, Representative Adam Schiff, the Democratic chairman of the House Intelligence Committee said on “CBS This Morning” that Barr should resign because he “deliberately” misled Congress when he testified he didn’t know whether Mueller agreed with his summary of the findings.

Republican Senator Lindsey Graham, the Judiciary panel’s chairman, opened the hearing by saying he was satisfied with Mueller’s report and said “for me, it is over.”

But Senator Dianne Feinstein, the committee’s top Democrat, said that Mueller’s report contained “substantial evidence of misconduct” and that the committee needed “to hear directly from the special counsel.”

Barr repeated his past statement that he’d have no objection to Mueller appearing before Congress, and Graham promised Mueller would have a chance to address any inaccuracies in Barr’s account of their conversations.

Justice Department spokeswoman Kerri Kupec said in a statement Tuesday evening that Barr called Mueller after receiving the special counsel’s letter.

“In a cordial and professional conversation, the special counsel emphasized that nothing in the attorney general’s March 24 letter was inaccurate or misleading,” Kupec said in the statement. “But, he expressed frustration over the lack of context and the resulting media coverage regarding the special counsel’s obstruction analysis.”

Barr said in his letter, and in a news conference shortly before the report was released, that Mueller had closed his inquiry without deciding whether President Donald Trump had obstructed justice. Barr said that meant he needed to make the decision. He said that he, along with Deputy Attorney General Rod Rosenstein, concluded that there wasn’t sufficient evidence for criminal charges.

Barr’s characterization of Mueller’s findings stood uncontested until a redacted version of Mueller’s report was released on April 18.

In fact, Mueller said he didn’t make a “traditional” prosecution judgment on obstruction, mainly because he decided to abide by a Justice Department policy that says a sitting president cannot be indicted.

Yet he cited at least 10 examples of efforts to interfere in the investigation and pointedly added, “If we had confidence after a thorough investigation of the facts that the president clearly did not commit obstruction of justice, we would so state. Based on the facts and the applicable legal standards, however, we are unable to reach that judgment.”

Defending Barr’s call on obstruction of justice, Graham said Mueller told the attorney general “‘Mr. Barr, you decide’ — and Barr did.” Mueller never made such a request.

‘Pattern’ of Obstruction

Senator Amy Klobuchar, one of three Democratic presidential candidates on the Judiciary panel, cited a litany of instances in Mueller’s report from which Trump signaled those around him should stay on message, indicating he’d have lawyer Michael Cohen’s back or calling former campaign chairman Paul Manafort “a brave man” for refusing to break under pressure from prosecutors.

“You look at the totality of the evidence and the pattern here” of obstruction, she said.

Barr replied that a prosecutor would have to show that Trump had “corrupt intent” and that his statement would have a “sufficiently probable effect.” He said there’s “ample evidence” backing Trump’s version that he wanted to prevent people from “succumbing to pressure” and lying.

Senator Kamala Harris, another of the presidential candidates and a former district attorney and attorney general in California, cross-examined Barr methodically. She got him to concede that neither he nor Rosenstein did his own review of the underlying evidence before declaring that Trump didn’t obstruct justice.

Barr also refused to answer her repeated questions about whether Trump or anyone in the White House suggested he open any particular investigation. “I think the American people can see quite well that you are biased,” she said.

Soon after, Harris tweeted, “What I just saw from the Attorney General is unacceptable. Barr must resign now.”

Graham and other Republicans renewed their call for an investigation into what he and other Republicans portray as anti-Trump sentiment that they say tainted the early stages of the Russia investigation and the 2016 investigation into Democrat Hillary Clinton’s use of a private email server. Barr affirmed that he’s looking into such issues, including what he’s previously called “spying” on Trump’s campaign. He said FBI Director Christopher Wray also was exploring that question.

While Democrats are in the minority of the Senate committee, a hearing scheduled for Thursday before the Democratic-led House Judiciary Committee may be more acrimonious — if it takes place. The Justice Department has resisted a format that would let the committee’s Democratic and Republican counsels grill Barr for as long as 30 minutes at a stretch after initial five-minute exchanges with lawmakers.

Judiciary Chairman Jerrold Nadler of New York, cited reports that Barr may refuse to appear under those ground rules. “No witness can simply dictate to this committee the manner in which he or she is questioned when it is fully in accordance with House rules,” Nadler said in a statement Wednesday.

A House subpoena issued by Nadler calls for the production of the entire report, and underlying material, by Wednesday.

Republicans on the House Judiciary Committee, however, expressed confidence in Barr’s handling of the release of the Mueller report, according to Jessica Andrews, a spokeswoman.

“House Democrats have another opportunity to put partisan politics aside and recognize Attorney General Barr has conducted himself in an exemplary manner,” she said Tuesday night.