“He will promise to do the right thing, and he will promise to protect the integrity of the Justice Department,” said one person familiar with Barr’s preparations,who, like others, spoke on the condition of anonymity to discuss candid insights.

Some Democrats have argued for Barr’s recusal from the Mueller probe because of his past public statements critical of some aspects of the investigation, and a private memo he sent to Deputy Attorney General Rod J. Rosenstein last June in which he called Mueller’s investigation into whether the president may have obstructed justice “fatally misconceived.” Barr also wrote that Mueller should not be allowed to subpoena the president about obstruction, saying an “interrogation” was not warranted.

One person close to Barr said he felt “very strongly” about the issue and wrote the memo hoping his advice might help officials who might be too busy to consider the issue thoroughly. Democrats have said his memo and past statements suggest a bias against the special counsel investigation.