WATCH: Former U.S. attorney explains why the Russia matter won't be resolved until Mueller testifies publicly to Congress
Robert Mueller testifies before Congress (screengrab)

In his resignation speech, special counsel Robert Mueller offered his own views on the Russia investigation, which were damning to President Donald Trump.

But as former U.S. Attorney Preet Bharara told CNN's Wolf Blitzer on Wednesday, Mueller's farewell address was not enough. The special counsel needs to testify before Congress, in a public setting.

"Mueller said he hopes this will be the only time he speaks publicly on his report," said Blitzer. "That if he has to testify before Congress, he won't go beyond what's actually written in his 448-page report. But are there more questions he should address?"

"I don't blame him for hoping that," said Bharara. "God forbid anyone should hope to testify in front of Congress, especially given some of the circus-like atmosphere we've seen when people come to testify. But I think there are questions he can answer."

"Look, people should remember, Bob Mueller has been mute for the last two years other than today, and he's a pretty reticent guy," said Bharara. "But he was the FBI director for 12 years, he was a U.S. attorney in multiple places. And he spoke. He would have work that he put forward that speaks for itself, like he said the report speaks for itself, like an indictment or criminal complaint."

"I've stood with him at press conferences, and notwithstanding the work speaks for itself as it always does," Bharara continued. "He understood in cases of high consequence and where people cared about them, there was some value in explaining things to the public and answering questions from the press, because not everything can be fully explanatory based on the words alone. And he's testified in front of Congress, he's actually pretty good at it. He may not like it. He may not like, you know, being in a position to look like he's politicizing the whole thing, because other people will be politicizing it."

"But there's lots of things he should be able to answer, including how we might protect ourself from attack in the future, including how he thought the special counsel process worked," Bharara said. "Congress has a role in trying to figure out if this process was good, if the special counsel regulations need changing. It's in the heartland, I think, of their responsibility and duty and obligation to figure out how it is you go forward in the future, how you investigate the president and what the special counsel's powers should be."

"And on top of all that, I would like to hear the special counsel, not just in a formal remark at the end of his statement defending his team and defending the integrity of the people who worked in the special counsel's office, but I'd like to see him in reaction to people making accusations that have flown from the president's mouth and other people," Bharara added. "Bob Mueller, with his integrity and with his track record and with his gravitas, explain why he thinks his team did the right thing and guard against accusations that are made. A lot of people hear an accusation made and because there's a broad statement defending the office, I think there's value having him say those things in Congress to an audience of millions."

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