Attorney general nominee William P. Barr generally acquitted himself well during the long day of testimony before the Senate Judiciary Committee on Tuesday. He gave the impression of someone who is his own man, unlikely to comply with the president’s orders, if any, to interfere with investigations. He stood up for special counsel Robert S. Mueller III, contradicting President Trump’s characterization of him and his investigation.

However, in one regard, his answer was off-target and worrisome. Sen. Mazie Hirono (D-Hawaii) asked, “Are you concerned about the way Donald Trump undermines the institutions in our society?” He gave the following answer: “We have to remember that the president is the one who has denied that there’s any collusion and has been steadfast in that.” He offered, “Presumably he knows facts [we don’t]. . . .”

In deeming Trump’s response “reasonable,” Barr substantially undercut his own argument that a president doesn’t get to, as Trump has said, do whatever he wants regarding the Justice Department.

Barr’s answer was suitable, I suppose, if the person complaining is a private citizen. Trump is not. He’s taken an oath to the Constitution, to take care that the laws are faithfully executed. In attacking Mueller on his own behalf (as the one under investigation), Trump put his own interests above the obligations of the president, which include the maintenance of a fair and professional Justice Department.

Indeed, Trump or his surrogates often say the president has the “right to defend himself.” Actually, only up to a point. If defending himself entails smearing the DOJ, sowing doubt about the criminal justice system and/or exerting undue pressure on the department, then he’s not upheld his oath.

“Bill Barr seemed to be channeling the awkward experience Justice Gorsuch had when he commented, as a not-yet-confirmed Supreme Court nominee, that the president’s attacks on ‘so-called judges’ were troubling to him,” says constitutional expert Larry Tribe. “Trump’s musings about pulling the Gorsuch nomination in the wake of that comment may have led Barr to avoid criticizing Trump’s intemperate and destructive attacks on the Department of Justice.”

In giving Trump an out, or even covering for him, Barr only encourages this and similar attacks on democratic institutions including the press, the independent judiciary and the rule of law more generally.

The next time Trump, as he surely will, attacks the FBI and/or the Justice Department when Barr is there, does he tell his department that it is “reasonable” for the president to behave in such a fashion? Barr. it seems. has an obligation to advise the president that such attacks are not “reasonable” and to inform Trump that he has a higher obligation than defending himself (granted, the concept will confuse Trump).

“I would expect any attorney general to stand up for the FBI, and to be critical of any government official who talks about 'rats’ and tries to get people not to cooperate with law enforcement,” says Neal Katyal, former acting solicitor general.

Alas, this is the inescapable dilemma of anyone who goes to work for this administration. To live up completely to your legal, ethical and professional obligations often means you cannot remain in the president’s good graces. The pressure to preserve one’s position too often leads one to compromise or ignore those obligations.

I would hope Barr rethinks his answer and follows up with the committee. More importantly, one hopes that, when Trump launches his next vicious, unsubstantiated attack, Barr stands up for his people. If he cannot, he shouldn’t take the job.

Read more: