Chris Coons, a Democrat, represents Delaware in the U.S. Senate and is a member of the Judiciary Committee.

In May of 1973, the Watergate scandal was reaching a fever pitch. Congress was investigating President Richard Nixon’s campaign and administration, and many Americans were concerned about the rule of law.

In the midst of this unfolding scandal, the Senate secured on-the-record commitments from Elliot Richardson, Nixon’s nominee for attorney general, during his confirmation hearing that he would appoint a Watergate special prosecutor, resist pressure from the White House and not fire the special prosecutor without cause.

This precedent is more relevant and important than ever as the Senate Judiciary Committee prepares to consider the nomination of William P. Barr, President Trump’s nominee for attorney general. Like Richardson, Barr has significant prior experience, having served as attorney general and in other senior positions at the Justice Department in President George H.W. Bush’s administration.

His confirmation hearing also comes at a time of national turmoil. Barr has been nominated by a president who has been implicated in criminal charges as “Individual 1,” whose close aides have been convicted or pleaded guilty to crimes, and who has made no secret of his desire to interfere with and even end special counsel Robert S. Mueller III’s investigation into possible collusion with Russia during the 2016 election and obstruction of justice.

Just as Richardson’s confirmation hearing helped ensure that the Justice Department would honor the principle that no one is above the law, Barr’s hearing represents a crucial moment for the independence of the department and the rule of law, which are at risk once again.

I met with Barr privately to discuss these concerns, and that meeting, along with his written testimony, left me with a number of unanswered questions. In the hearing this week, I will press him to demonstrate that he will be an attorney general committed to upholding the Constitution and applying the law without fear or favor. I will be looking for unequivocal commitments that he will respect the independence of Mueller’s investigation; that he will ensure it receives all of the resources it needs; that he will not overrule Mueller’s decisions about indictments and prosecutions; and that he will not allow anyone, including the president, to interfere with or curtail the investigation.

I would expect that from any nominee for attorney general, but Barr’s previous positions on the special counsel investigation and executive power suggest ample reason for concern.

Barr wrote an unsolicited memo that he sent to Deputy Attorney General Rod J. Rosenstein on June 8, 2018, openly attacking the Mueller investigation, claiming its theory of obstruction was “insupportable” and “would do lasting damage to the presidency.” He argued that the president can appoint or remove officials, use his prosecutorial discretion to give direction on a case and issue pardons — even if he were covering up his own wrongful conduct.

These criticisms, as well as his views on criminal-justice reform, LGBTQ rights, civil rights and the independence of the Justice Department, merit thorough inquiry by members of the Senate Judiciary Committee.

We need to know if Barr will commit to complying with and defending the Special Counsel Independence and Integrity Act , should that bill become law. The legislation, which I co-wrote with Senate Judiciary Committee Chairman Lindsey O. Graham (R-S.C.), Sen. Thom Tillis (R-N.C.) and Sen. Cory Booker (D-N.J.), would prohibit the president from firing the special counsel without good cause.

We also need to know whether he would uphold the commitment he made during a previous confirmation process as to what he would do if an administration official was pursing an illegal act. At the time, Barr stated: “I would do all within my power to prevent the wrongdoing. If other means failed, I would resign my position rather than be a party to ongoing violations of the law.”

We need to know if Barr will make that same commitment today, even if the person violating the law is the president of the United States.

In October 1973, less than five months after Richardson became attorney general, he resigned rather than fire special prosecutor Archibald Cox on Nixon’s orders, citing the commitment he made to the Senate to “assure the independence of the special prosecutor.” His resignation led to the Saturday Night Massacre, the appointment of another special prosecutor to protect the rule of law and exposure of criminal wrongdoing by President Nixon.

We are at another pivotal point in our nation’s history. We can either stand up and protect the rule of law, as we have before, or stand by as a key pillar of our democracy threatens to crumble before our eyes. Barr’s confirmation hearing will be a critical test to see which path we will take.

Read more: