In 1973, attorney general Elliot Richardson refused to carry out Richard Nixon’s order to shut down the Watergate investigation and resigned in protest. William P. Barr, Donald Trump’s new nominee for attorney general, should promise to follow Richardson’s example by refusing to comply with an order to interfere with the ongoing investigations of the president. If Barr does not make that commitment, the Senate should not confirm him.

Trump is reportedly implicated in at least three ongoing federal criminal investigations, including Robert Mueller’s probe into Russian interference in the 2016 campaign; a probe of Trump’s illegal hush money payments to two women; and an inquiry into possible illegal foreign contributions to Trump’s inauguration festivities. Upon confirmation, Barr could supervise each of these investigations.

Only one other attorney general entered the office under similar circumstances. In April 1973, Nixon nominated Richardson in the midst of the Watergate scandal. Richardson immediately named Archibald Cox to serve as Watergate special prosecutor; Richardson also vowed he would not control Cox’s investigation, and promised the Senate that he would fire Cox only for extraordinary impropriety.

In October 1973, Nixon directed Richardson to fire Cox and shut down his investigation. Richardson and his deputy refused the order and resigned in what became known as the Saturday Night Massacre. While solicitor general Robert Bork fired Cox, Nixon’s gambit backfired; the nation recognized Richardson had stood up for the fair operation of the justice system in the face of Nixon’s overreach. Nixon was forced to agree to the appointment of Leon Jaworski as Cox’s replacement. Jaworski successfully petitioned the Supreme Court to order Nixon’s hand over of the White House tapes, which included recordings that ultimately led to the president’s resignation.

Today the nation requires confidence that Barr would likewise refuse any order by Trump to interfere with the investigations of the president and his associates. There are, however, many reasons for concern that Barr may not meet to standard Richardson set.

Barr served in President George H.W. Bush’s Justice Department, including as attorney general. Barr became known as a proponent of the so-called “unitary executive” doctrine, which, in its strongest form, holds that all federal officers, agencies and commissions must be under the direct control of the president. Barr also facilitated Bush’s pardons, immediately before leaving office, of six individuals who had been convicted or charged by Iran-Contra Independent Counsel Lawrence Walsh, including the indicted former Secretary of Defense Casper Weinberger. Bush’s last-minute wave of pardons effectively ended Walsh’s investigation, and with it a probe into Bush’s own conduct.

More recently, Barr has defended Trump’s efforts to influence investigations of himself, as well as his political opponents. Barr defended Trump’s firing of FBI Director James Comey, despite Trump’s admission that he removed Comey because the FBI was investigating Russian interference in the 2016 election. Barr also endorsed Trump’s successful efforts to pressure then attorney general Jeff Sessions to pursue a speculative claim, initially advanced by Steve Bannon, that Hillary Clinton illegally assisted a Russian company purchase U.S. uranium assets. Barr asserted that there’s “nothing inherently wrong” about a president pressing for an investigation of a political opponent, if the investigation is potentially meritorious.

Barr has made even broader arguments in Trump’s favor in private. In June 2018, Barr sent a confidential memo to Deputy Attorney General Rod Rosenstein contending that Mueller should be barred from questioning Trump about the Comey firing. Barr asserted that the matter should not even be investigated because the president has an “illimitable” authority to “start or stop a law enforcement proceeding” on account of the “unitary” nature of the executive branch. Barr also suggested that Trump cannot ever be subject to criminal liability arising from his grant of pardons, even if Trump hands pardons out as part of a scheme to silence potential witnesses against him.

Barr’s claim that Trump has a constitutional right to shut down investigations of himself bears remarkable similarity to arguments Trump’s defense team have been advancing, and that may not be a coincidence. Trump reportedly asked Barr to serve as his personal lawyer in 2017; while Barr reportedly declined the offer, he may have continued to communicate with Trump’s attorneys until during sometime this year.[8] There are also reports Barr may have shared copies of his confidential Rosenstein memo with Trump’s lawyers.

As Former Acting Solicitor General Neal Katyal has explained, if Barr confidentially shared his own views and opinions on the ongoing investigations with Trump’s defense team, he may properly be disqualified from overseeing the probes. That is because it’s improper for the subject of a criminal investigation to be privy to the personal judgments and legal opinions of the prosecutor investigating them. Furthermore, Barr’s emphatic public and private endorsements of Trump’s defenses may also raise a sufficient appearance of bias to mandate Barr’s recusal.

Accordingly, the Senate should demand full disclosure of all of Barr’s prior communications with Trump and his defense team, and should likewise obtain Barr’s agreement to, like Sessions, both seek and comply with a formal DOJ ethics opinion on whether his recusal is appropriate. Acting Attorney General Whitaker made the unprecedented decision to disregard the opinion of a DOJ ethics expert on these matters, making it all the more important that Barr provide such a commitment,

Most importantly, if Barr is permitted to supervise any investigations involving the president, the Senate should demand he provide the “Richardson promises,” including a promise that Barr will not fire any prosecutors investigating the president, nor interfere with their probes, absent extraordinary impropriety, even if Trump order him to do so. The Senate should likewise require that Barr commit to disclose the contents of any report Mueller submits to the maximum extent permissible under applicable law.

Barr’s expansive views of presidential authority make it all the more important that he provide such assurances; furthermore, his extreme views should pose no barrier to his doing so. Richardson believed that Nixon had the legal authority to order Cox’s firing, but nonetheless refused to carry out the president’s order because of the promise he had made to the Senate. Accordingly, if Barr refuses to make the Richardson promises, he will simply be unfit to serve as the nation’s chief law enforcement officer.