(Jenny Starrs/The Washington Post)

Matthew Miller was director of the Justice Department’s public affairs office from 2009 to 2011.

President Trump’s decision on Monday night to fire acting attorney general Sally Yates for daring to exercise her objective legal judgment about the president’s recent immigration order violated the traditional independence of the Justice Department and sets a dangerous precedent for the rule of law under his administration.

Under long-standing traditions in administrations of both parties, the attorney general is charged with enforcing the law free from political interference from the White House. This standard of independence, unique among Cabinet members, is designed to insulate questions of law from inappropriate political pressure, and presidents and attorneys general who have violated that standard have typically paid a grave price for doing so.

The legality of the underlying executive order is hotly debated. Four federal judges have already halted the administration from enforcing various aspects of it, and people affected by the ban continue to bring new lawsuits. The Justice Department’s Office of Legal Counsel did apparently approve the order on the narrow basis of “form and legality,” but since the Trump administration has not released a copy of the office’s opinion or answered questions about whether it raised any objections, we do not know the extent of its analysis.

Yates clearly had profound doubts about the order’s legality. In her letter to Justice Department employees, she implied that Trump’s references in interviews and tweets to giving preferential treatment to Christian refugees revealed the order’s true discriminatory intent, something that would render it unlawful.

But whatever one thinks about the executive order, the more fundamental issue is that in this case the decision whether to defend it in court rested not with the president, but with the attorney general. When Yates raised her objections to the order, she noted that she remained open to being convinced of its legality. The White House, which did not consult with her or other Cabinet members in drafting the order, could have worked with her to make changes that would satisfy her concerns about its legality. Instead, the president chose crisis and chaos.

The White House’s statement announcing her firing revealed the political nature of Trump’s decision. It accused Yates — a career prosecutor with 25 years experience of putting violent criminals behind bars — of having betrayed the Justice Department. Instead of even attempting to wrestle with any questions of the attorney general’s proper role, the White House attacked Yates as being “weak on borders and very weak on illegal immigration.”

Earlier on Monday, White House press secretary Sean Spicer had announced that career State Department officials who disagreed with the president’s immigration order should “either get with the program or they can go.” In its attack on Yates, the White House made clear the president expects the same level of quiet obeisance from his attorney general.

This is not the first time that Trump has shown he does not respect the Justice Department’s independence. During the campaign, he promised to appoint a special counsel to prosecute Hillary Clinton, and as president-elect he waded into the department’s territory again, saying he changed his mind and would not prosecute her. Neither statement was appropriate. Those decisions, like other decisions about investigative matters, are to be made solely at the Justice Department without White House pressure.

This disrespect for the department’s traditional independence would be troubling from any president, but it is especially so from one whose campaign associates are currently under investigation for possible ties to Russian interference in the election. The next attorney general will oversee that investigation and be charged with executing it faithfully. He or she will also be charged with probing any accusations of corruption inside the Trump administration, or whether at any point the president’s vast business holdings — which he refuses to divest — lead him to violate federal bribery or conflict-of-interest statutes.

The ability of Sen. Jeff Sessions (R-Ala.), Trump’s nominee for attorney general, to decide these matters fairly was already under question. Sessions was not just a Trump supporter during the election, but also an active and official member of Trump’s campaign, serving as chair of its national security advisory committee. Nevertheless, he has refused to commit to recusing himself from the Justice Department’s investigation into Trump campaign members despite department rules that clearly require him to do so.

Trump’s actions on Monday have now raised the ante for the Senate. Recusal might have previously been enough to put to rest concerns about Sessions’s independence, but now that Trump has made clear he expects his attorney general to follow orders without questioning them, the Senate must respond by rejecting that notion and showing it will confirm only someone who is truly independent. Sessions does not clear that bar.

There is no law that establishes the Justice Department’s independence. Like many democratic norms, it has rested on faithful adherence by committed public servants, attorneys who are willing to make independent judgments, and the oversight of Congress and the free press. Trump just made clear that he does not respect this tradition. It now falls to the rest of us to show that we do.