Attorney General nominee William Barr assured senators that he would not fire special counsel Robert S. Mueller III without good cause or change Justice Department regulations for the purpose of firing him.

“I would resign rather than follow an order to terminate the special counsel without good cause,” Barr said in written answers to questions from Senate Judiciary Committee members released Monday.

Barr asserted his independence from the White House during his Jan. 15 confirmation hearing but he did not say that so directly, testifying only that he would “not carry out that instruction.” He also said, “Frankly it’s unimaginable to me that Bob would ever do anything that gave rise to good cause.”

That prompted several senators to ask follow-up questions about whether he would protect the Mueller-led investigation into connections between President Donald Trump’s campaign and Russian interference in the 2016 election.

Barr also gave more details in the written answers on several high-profile topics.