Sen. Dianne Feinstein said Wednesday that she would not vote for attorney general nominee William P. Barr unless he were to commit to releasing the report generated by the special-counsel investigation — something he has notably declined to do.

On the second day of Barr’s confirmation hearing, Feinstein (D-Calif.), the highest-ranking Democrat on the Senate Judiciary Committee, praised the nominee’s answers to questions about special counsel Robert S. Mueller III, saying he “clearly understands the need for independence and the importance of protecting the department, as well as Mr. Mueller, from interference.”

But she quickly added that Barr’s description of what he would do with Mueller’s final report was “confusing” and that she could not vote for him unless he committed to releasing it.

“This is a big report, and the public needs to see it, and with exception of very real national security concerns, I don’t even believe there should be very much redaction,” Feinstein said. “So, I am hopeful that that report will be made public, and my vote depends on that, Mr. Chairman, because an attorney general must understand the importance of this to the nation as a whole, to us as a Congress, as well as to every American.”

Because Republicans control the Senate, Barr does not need any Democratic votes to win confirmation — meaning Feinstein’s support would be a mere feather in his cap. But the senator from California had seemed supportive of Barr during his nine hours answering questions Tuesday, even noting during the proceeding that it was “going very well” and she expected Barr to be confirmed.

She said in an interview Wednesday: “My decision is all around the report coming out. It can’t be stopped, interfered with, defunded — it’s got to finish, and there has to be a commitment by this attorney general that that report will be released publicly.”

On Wednesday, lawmakers questioned advocates, legal experts and colleagues of Barr about his record and character, and about how he might handle the Mueller investigation. Barr testified Tuesday, and much of that discussion also centered on Mueller’s investigation and whether Barr would seek to influence the outcome of the probe.

Barr, who previously served as attorney general under President George H.W. Bush in the early 1990s, pledged to let Mueller finish his work and release as much information about his findings as possible, but he cautioned that Justice Department regulations may prevent any report written by Mueller from being made public.

“The rules, I think, say the special counsel will prepare a summary report on any prosecutive or declination decisions, and that shall be confidential and be treated as any other declination or prosecutive material within the department,” Barr said Tuesday.

Senate Minority Leader Charles E. Schumer (D-N.Y.) echoed Feinstein’s concerns, saying Barr’s broad goal of transparency was “not good enough.”

“To merit a vote on nomination you would have to make unequivocal and public that you would not interfere with the issuance, you would issue the full report, except if intelligence sources said certain portions should be redacted,” Schumer told reporters Wednesday.

Schumer had already pledged to vote against Barr’s nomination before a meeting with him Wednesday afternoon in which said he hoped that the nominee might “undo my opposition” by being more forthcoming than he was in Tuesday’s hearing. He wasn’t, Schumer said.

Sen. Christopher A. Coons (D-Del.) said Barr was “experienced and seasoned and in some ways is the sort of Department of Justice institutionalist one might hope for in a very rocky period.” But he said Barr “evaded several of my direct questions in terms of making a clear and simple commitment to the full release of the Mueller report, to seeking and following the advice of Department of Justice career ethics counsel, and to allowing Mueller . . . to make his own decisions about seeking testimony from the president.”

Coons said he was going to give Barr a chance to address his concerns and make a firmer commitment to allowing Mueller to do his work and release his report free from interference.

The witnesses that appeared in support of Barr on Wednesday included former attorney general Michael B. Mukasey and Chuck Canterbury, president of the Fraternal Order of Police. Also appearing before the committee were NAACP President Derrick Johnson and former deputy attorney general Larry D. Thompson.

Addressing whether Barr would release the Mueller report, Jonathan Turley, a legal scholar, testified that Barr could not “satisfy ethical standards” while committing in advance to releasing information “he hasn’t seen yet.”

“The only thing a nominee can say is that he is going to err on the side of transparency,” Turley said.

The Senate could vote on Barr’s confirmation next month.