I worked at the Justice Department for 25 years, most of them as a line prosecutor. For the last seven and a half of those, I served as the U.S. attorney in the Northern District of Alabama. I didn’t work in the Justice Department’s headquarters building in Washington, or in the legendary U.S. Attorney’s Office in the Southern District of New York, but I shared the same understanding with the prosecutors who did—and with others across the country—that our integrity was our most important asset. We were careful stewards of the public’s faith in our offices so we could pass it along to those who came after us.

We cannot permit recent news about the current and future leadership of the Justice Department to be relegated to the bottom of the stack after the holiday news cycle. Last week we learned that Trump’s acting attorney general, Matthew Whitaker—the man Trump bypassed Senate-confirmed officials like the deputy attorney general and solicitor general to put in place—will not only ignore career ethics officials at DOJ who believe he should recuse from the Mueller investigation, but also had discussions with Trump about Michael Cohen’s ongoing prosecution in the Southern District of New York. Trump was directly implicated by prosecutors in that case as an unnamed participant in criminal conduct. The president told Whitaker he was angry with SDNY prosecutors and “pressed Whitaker on why more wasn’t being done to control” the prosecutors, who he suggested were “going rogue,” according to CNN.

That the president of the United States asked his acting attorney general to rein in prosecutors who are investigating the president’s conduct is mind-boggling. For Trump, prosecutors who do their job are rogues.

When Trump made his now-infamous Oval Office request to former FBI Director Jim Comey that he go easy on Mike Flynn, Comey understood it to be an order. There is no reason to believe Whitaker, who auditioned for the role of attorney general with television appearances that laid out how an attorney general could starve the Mueller investigation, is less perceptive at detecting an order given by the president. No attorney general should tolerate interference into a criminal investigation by someone who is a subject of that investigation. Yet Whitaker appears willing to do just that. Without fear or favor doesn’t mean only when it’s easy. If the president is above the law, who’s next?

Prosecutors are charged with maintaining the rule of law and insuring that no one, not even the president, is above the law. This means their own conduct must be unimpeachable. That’s why prosecutors guard against both actual impropriety and even the appearance of impropriety.

In this context, the selection of the next attorney general is even more critical. News that Trump’s apparent pick for the job, Bill Barr, sent an unsolicited 20-page memo to DOJ clearing the president of obstruction of justice—which also made its way to the White House—is deeply troubling. The country needs an attorney general it can trust, someone who will restore independence and integrity to the department.

No matter what Barr’s intentions, the appearance of impropriety—of ingratiating himself with a president whose desire to install a wingman as attorney general—means that the public perception will always equate Barr, if confirmed, with Trump’s desire to hold himself above the law. There will be no public confidence in decisions about potential collusion between the Trump campaign and Russia, or about obstruction of justice. Such a significant loss of public confidence will inevitably erode the credibility of the department’s work in other areas as well. The future of the Justice Department, and that of all Americans, will be impaired if it appears the department is being used as a tool to protect this president.

Recusal is not a sufficient remedy for a faulty choice for attorney general at this critical juncture. Congress has the responsibility to deny confirmation to an attorney general who is not suited for the job. A worthy nominee faced with the knowledge that they, even inadvertently, had damaged DOJ’s credibility would make amends if possible, or take themselves out of the running to ensure the people’s faith in justice. It is hard to believe someone who makes serious missteps, as Whitaker and Barr both have, but remains unwaveringly in place will have the fortitude to pass the challenges Trump’s next attorney general will certainly face.

When prosecutors talk about integrity, they talk about a reservoir: It is slow to fill with water and takes years of careful nurturing to fill. One small leak can permit the water to escape and it is difficult if not impossible to refill the reservoir after that.

If Congress confirms an attorney general nominee who is believed to work for the president, not the people, concern that DOJ’s independence from the White House is compromised will become a certainty. The implications of losing public confidence in our justice system are far greater than concerns about just this president. If people question the justice system itself and the integrity of the people who administer it, then DOJ’s reservoir will be empty long after this administration ends.

An attorney general selected because they would extricate the president from legal trouble should not be confirmed. The country has many fine conservative legal minds who are well-qualified to be attorney general. It should not be challenging to pick one among them, making it all the more suspicious when Trump only picks those who have spoken out in his favor.

Senate Republicans have the opportunity to insist that the president send them a nominee who is impeccably qualified and ethically above reproach. They must refuse to confirm one who isn’t. This is a red line the Senate must insist on. An attorney general cannot be a partisan or a protector of the president. They must commit to permitting investigations to go where the facts take them, to DOJ’s independence from the White House, and to the rule of law. Senate Republicans must themselves commit to these three principles, too, when they reconvene in January. There is too much at stake for them to permit DOJ’s integrity to be irrevocably sullied by this president.