Attorney General William P. Barr arrives for a news conference at the Justice Department in April. (Brendan Smialowski/AFP/Getty Images)

Democrats and the Justice Department are in a standoff over the terms of Attorney General William P. Barr’s planned testimony before the House Judiciary Committee this week, raising the prospect that the hearing might not go forward at all.

A senior Democratic committee aide said Sunday that Barr risks being subpoenaed if he refuses to testify over his objections to the lawmakers’ desired format for the hearing.

Barr is expected to appear before the Senate and House Judiciary committees Wednesday and Thursday, respectively, to address questions about special counsel Robert S. Mueller III’s report on Russian interference in the 2016 election. But according to senior aides for the panel’s chairman, Rep. Jerrold Nadler (D-N.Y.), Justice Department officials have objected to Democrats’ plans to permit extended questioning, including by the committee’s lawyers, and threatened that Barr may withdraw.

A Justice Department official said discussions are ongoing.

“The attorney general agreed to appear before Congress,” Justice Department spokeswoman Kerri Kupec said in a statement. “Therefore, members of Congress should be the ones doing the questioning. He remains happy to engage with Members on their questions regarding the Mueller report.”

The dispute amplifies what has become a tense political battle between Democrats and the Justice Department, with lawmakers accusing the attorney general of maneuvering to protect President Trump by characterizing Mueller’s findings in an overly sympathetic light.

Democrats maintain that statements and letters Barr issued before releasing Mueller’s redacted report have helped Trump make a case to the public that the special counsel investigation exonerated him, despite what they believe to be a wealth of incriminating evidence detailed throughout the 448-page document. A televised hearing is seen among lawmakers as their opportunity to hold Barr to account and make their case to the American people.

Daniel Schwarz, a spokesman for Nadler, said Sunday, “It would be a shame if Barr refused to show up for the hearing, but it is important that there be a chance to ask follow-up questions as has been done in the past, and members should not be prohibited from asking about redacted sections of the Mueller report, which means we would need to go into executive session in order for Barr to be able to answer in a secure setting.”

The dispute began Thursday, when the committee’s Democratic staff spoke to the Justice Department’s Office of Legislative Affairs about the intended format for the hearing.

Democratic members think it’s important, given Barr’s past testimony and what they viewed as his attempt to shape the narrative on Mueller’s report, that he be subjected to extended questioning, including by committee lawyers, said one congressional aide familiar with the matter, who spoke on the condition of anonymity because of the sensitivity surrounding Mueller’s report. Ordinarily, each member gets five minutes for questioning.

Democratic lawmakers “have seen administration witnesses filibuster for 4½ minutes, then say something nonresponsive in the last half-minute,” the aide said. “The Democratic members have been nearly unanimous in their opinion that circumstances warrant extended questioning, including by counsel.”

Democrats also want to reserve the right to vote to have Barr participate in a closed-door session following his public hearing to address questions about the information that remains shrouded by redactions in Mueller’s report, aides said.

But according to Nadler aides, Barr’s team objected to that proposal as well and said such a demand would prevent Barr from delivering his testimony as anticipated.

A Justice Department official came back to the committee Democrats on Friday “very worked up about” Nadler’s plan, and said that if the Democrats insisted on following their plan, Barr “might not come,” the aide said.

“The chutzpah of telling us how the hearing is going to be structured and then threatening to walk goes directly to our working thesis that [Barr] is interested in carrying water for the president but not interested in providing answers to the public,” the aide said.

The committee staff have researched other instances in which committee lawyers have questioned Cabinet officials during open congressional hearings, the aide said. The last time was during the 1980s, when President Ronald Reagan’s attorney general, Edwin Meese, gave testimony during the Iran-contra hearings, the aide said.

“The attorney general can choose to come in voluntarily under the chairman’s framework or risk being subpoenaed at a later date,” the senior aide said.

Barr and Democrats have long been at odds over the Mueller report and how the attorney general has handled its rollout. Many Democrats say Barr misrepresented Mueller’s findings in his public statements before the report’s release, and the party as a whole is frustrated that Barr has not taken further steps to ensure that all members of Congress are able to view the information that was redacted.

Barr’s most recent offer was that a select group of lawmakers, including several committee chairs, be allowed to view the redacted information, except for passages that cite grand jury testimony. Democrats have rejected that offer, arguing that more members and staffers should be privy to the redactions, and that Barr should assist lawmakers in seeking a court order to release the grand jury testimony to them.

A spokesperson for committee Republicans said Barr “wasn’t asked to testify before the committee — he offered.” The attorney general provided the Mueller report voluntarily and invited Democratic leaders to view a less-redacted version of the report in person, said the spokesperson, who like others spoke on the condition of anonymity to discuss sensitive information.

“Yet the only thing, apparently, that will satisfy Democrats, who refuse to read the less-redacted report, is to have staff pinch-hit when a Cabinet-level official appears before us,” the spokesperson said. “What actual precedent is there for our committee making such demands of a sitting attorney general as part of our oversight duties? The attorney general isn’t a fact witness, and this committee’s investigations — as Democrat leadership reminds us daily — don’t constitute impeachment, so Democrats have yet to prove their demands are anything but abusive and illogical in light of the transparency and good faith the attorney general has shown our committee.”

Matt Zapotosky and Rachael Bade contributed to this report.