Andrew Coan is a professor of law at the University of Arizona and author of the book “Prosecuting the President: How Special Prosecutors Hold Presidents Accountable and Protect the Rule of Law.”

President Trump’s nominee for attorney general, William P. Barr, testified Tuesday at his long-awaited confirmation hearing before the U.S. Senate. For Democratic senators and others concerned about special counsel Robert S. Mueller III’s investigation, the first day of that hearing was a mixed bag. Under intense questioning from both sides of the aisle, Barr expressed strong confidence in Mueller’s integrity and a full-throated commitment to maintaining the rule of law. Nevertheless, Barr scattered hints throughout the hearing of his broad views of executive power — as expressed most notably in a June 2018 memo challenging Mueller’s supposed theory of obstruction of justice.

Here is a rundown of the good, the bad and the uncertain from Tuesday’s hearing:

The Good

  • Barr pledged that Mueller “will be allowed to complete his work.”
  • Barr enthusiastically celebrated the Justice Department’s tradition of political independence.
  • Barr committed to transparency about Mueller’s report. He flatly refused to go along with the suggestion from Trump’s lawyer, Rudolph W. Giuliani, that the president be allowed to “correct” the report. “That will not happen,” Barr said.
  • Barr acknowledged that a president can obstruct justice by intimidating witnesses or destroying evidence, which Trump has arguably done in the months since Barr wrote his famous memo by dangling pardons and praising witnesses for not cooperating with Mueller’s investigation.
  • Barr explicitly stated that “it would be a crime” if the president promised a pardon in exchange for a witness’s exculpatory testimony. Breaking more new ground, he also stated that it would violate the Constitution for the president to shut down an investigation to protect himself or his family.
  • If Mueller is pursuing either of these angles, Barr’s testimony might be used to support the case that Trump obstructed justice — and even the case for impeachment.
  • Finally, Barr committed to resigning rather than fire Mueller without good cause, just as then-Attorney General Elliot Richardson did when President Richard M. Nixon fired Watergate Special Prosecutor Archibald Cox.

The Bad

  • Barr refused to condemn Trump’s vituperative criticisms of the Mueller investigation and the Justice Department officials overseeing it.
  • Barr’s promise to allow Mueller to complete his work could be read as being limited to Mueller’s investigation of collusion.
  • Barr continued to defend a memo he sent to the Justice Department last year in which he criticized part of Mueller’s investigation. He also misleadingly characterized that memo as hypothetical and narrowly focused on “one theory in particular … under a specific statute.”
  • In fact, Barr’s memo is premised on a broad and extreme theory of presidential power. If that theory is right, Nixon did not obstruct justice when he ordered the CIA to limit the FBI’s Watergate investigation on bogus national-security grounds.
  • Barr also admitted that he shared this memo with the president’s lawyers — meaning he effectively volunteered to assist the defense in the investigation he would be charged with supervising as attorney general.

The Uncertain

  • Barr was much less staunch in his defense of the U.S. attorney’s office investigating campaign-finance violations by former Trump lawyer Michael Cohen, allegedly at the direction of then-candidate Trump. He said he “would not stand for” interference with a lawful investigation but insisted on the president’s power to fire political appointees, a category that includes U.S. attorneys.
  • Barr committed to consult with government ethics lawyers about recusal from the Mueller investigation, but he would not firmly commit to abide by their decision.
  • Barr refused to commit to releasing Mueller’s full report to Congress or to the public, repeatedly emphasizing — correctly — that the special counsel regulations make the report “confidential” in the first instance. He also repeatedly mentioned Justice Department regulations that could be interpreted to constrain disclosure of portions of the report. This leaves Barr significant room to maneuver if he so chooses.
  • If Barr is not confirmed, that would keep Matthew G. Whitaker — a political loyalist of far weaker credentials — in charge of the Justice Department. This gives Mueller’s Senate defenders a difficult and uncomfortable choice.

The Bottom Line

With a Republican Senate majority, Barr’s confirmation is nearly a foregone conclusion, and his testimony on Day 1 unquestionably allows him some troubling wiggle room. But Tuesday’s public statements will have lasting consequences and provide grounds for cautious optimism. And there may be more to come on Day 2.

About one thing, Barr is indisputably correct: “It is vitally important that the special counsel be allowed to complete his investigation. … The country needs a credible resolution of these issues.” If he is confirmed, let us hope that he lives up to the spirit — and not just the letter — of this testimony.

Read more:

Erik Wemple: William Barr on jailing journalists: ‘I know there are guidelines in place’

Jennifer Rubin: Why would William Barr want to join this White House?

Elizabeth Holtzman: I was in Congress during Nixon’s impeachment proceedings. William Barr is wrong.

William Barr: Trump made the right call on Comey

The Post’s View: Rod Rosenstein protected the Justice Department’s integrity. William Barr must do the same.