Back in 2015, when the idea of Donald Trump in the Oval Office seemed far-fetched, Jeff Sessions wanted to know whether Sally Yates was willing to stand up to the president.

“You have to watch out, because people will be asking you to do things you just need to say no about,” the Alabama senator told her during her confirmation hearing to become deputy attorney general. “Do you think the attorney general has the responsibility to say no to the president if he asks for something that’s improper? A lot of people have defended the Loretta Lynch nomination, for example, by saying: ‘Well, he appoints somebody who’s going to execute his views. What’s wrong with that?’ But if the views the president wants to execute are unlawful, should the attorney general or the deputy attorney general say no?”

“Senator, I believe that the attorney general or the deputy attorney general has the obligation to follow the law and the Constitution, and to give their independent legal advice to the president,” Yates said.

Sessions, who will soon be attorney general, circled back to the issue: “Like any CEO, with a law firm – sometimes the lawyers have to tell the CEO: ‘Mr. CEO, you can’t do that. Don’t do that. We’ll get us sued. It’s going to be in violation of the law. You’ll regret it, please.’ No matter how headstrong they might be. Do you feel like that’s the duty of the attorney general’s office?”

Yates assured him: “I do believe that that’s the duty of the attorney general’s office, to fairly and impartially evaluate the law and to provide the president and the administration with impartial legal advice.”

Just as it turns out Trump literally meant what he said on the campaign trail and planned to follow through, on Monday night Yates was true to her word. The acting attorney general ordered Justice Department lawyers not to defend Trump’s immigration order temporarily banning entry into the United States for citizens of seven Muslim-majority countries and refugees from around the world. She was promptly fired.

Trump’s order was reviewed by the Justice Department’s Office of Legal Counsel before it was issued. But Yates said in a memo explaining her decision that the OLC failed to take into account intent, which is relevant in a court of law. Over the weekend, Rudy Giuliani (who is lunching with the president Tuesday) went on Fox News to say that Trump told him he wanted to have a “Muslim ban” and requested that the former New York mayor work with experts to show him “the right way to do it legally.” (Any kind of religious test would be plainly unconstitutional.)

ACTION RAISES QUESTIONS

Trump’s move Monday night, while legally defensible, raises fresh questions about the president’s commitment to the rule of law. It follows several episodes during the campaign that were far outside American norms.

Recall when he said that a federal district judge, Gonzalo Curiel, could not properly adjudicate a fraud lawsuit against Trump University because his parents were born in Mexico. (Paul Ryan called this the textbook definition of a racist statement.)

At a debate in October, Trump said he would “instruct the attorney general to get a special prosecutor to look” into Hillary Clinton if he got elected. “It’s awfully good someone with the temperament of Donald Trump is not in charge of the law in our country,” Clinton said. To which Trump replied, “Because you’d be in jail.”

It is against the law to waterboard terrorism suspects, yet Trump suggested several times last week that he might still order it.

The decision to fire Yates also raises profound questions about Trump’s view of the judiciary as an independent branch of government. Firing Yates gives Democrats more fodder to rigorously scrutinize Trump’s nominee for the Supreme Court. What kind of conversations has the president had with this person? Did he ask him to make any commitments about anything? Would Trump stop himself, or would anyone on his staff stop him, from calling this justice directly to complain about something he doesn’t like or to press him on a case that’s before the high court?

TRUMP DESCRIBES WHOM HE’D PICK

Trump was asked during an appearance on ABC’s “Good Morning America” last spring what kind of person he’d pick to replace Antonin Scalia. His answer? Someone who “would look very seriously at (Hillary’s) email disaster.” “Well, I’d probably appoint people that would look very seriously at her email disaster because it’s a criminal activity, and I would appoint people that would look very seriously at that to start off with,” Trump said. “You talk about a case. Now that’s a real case. If she’s able to get away with that, you can get away with anything.”

Judges in our system have nothing to do with investigating or prosecuting crimes, of course, but it’s not clear Trump understood that when he made the comment.

Trump said last month that he would not name his Supreme Court pick until after Sessions was confirmed as attorney general. Sessions hasn’t cleared the Judiciary Committee yet, let alone the full Senate, but Trump is going forward with the announcement. Last week, Trump said he would make the announcement on Thursday. Then he moved it up to Tuesday. Sean Spicer was asked why during his briefing Monday. “Because he wanted to,” the press secretary said.

That’s a refreshingly honest answer in some ways, but it also encapsulates Trump’s approach to the presidency thus far.

Trump has hung a portrait of Andrew Jackson next to his desk in the Oval Office, the latest data point to show how he sees himself as the natural heir to the Jacksonian tradition. In 1832, when the Supreme Court struck down a Georgia law that allowed for the seizure of Cherokee lands, both the state and Jackson just ignored it. It’s possibly apocryphal, but the seventh president is purported to have said: “John Marshall has made his decision. Now let him enforce it.”

Monday night’s donnybrook makes it very hard for any Senate Democrat, with the possible exception of Joe Manchin, to confirm Sessions when he comes up for a vote on the floor. The blowback from the base and leadership would be intense.

SESSIONS INVOLVED IN HARD-LINE ACTIONS

Sessions has been the intellectual godfather of all Trump’s hard-line actions thus far. Robert Costa and Philip Rucker have a fantastic story about his influence: The author of many of Trump’s executive orders is senior policy adviser Stephen Miller, a Sessions confidant who was mentored by him and who spent the weekend overseeing the government’s implementation of the refugee ban. The tactician turning Trump’s agenda into law is deputy chief of staff Rick Dearborn, Sessions’ longtime chief of staff in the Senate.

The mastermind behind Trump’s incendiary brand of populism is chief strategist Stephen Bannon, who, as chairman of the Breitbart website, promoted Sessions for years. Then there is Jared Kushner, the president’s son-in-law and senior adviser, who considers Sessions a savant and forged a bond with the senator while orchestrating Trump’s trip last summer to Mexico City and during the darkest days of the campaign.

Bannon emailed The Post that Sessions is “the clearinghouse for policy and philosophy” in Trump’s administration, saying he and the senator are at the center of Trump’s “pro-America movement” and the global nationalist phenomenon: “What we are witnessing now is the birth of a new political order, and the more frantic a handful of media elites become, the more powerful that new political order becomes itself.”

Keep in mind: Because he knows he has the votes to get confirmed, Sessions has repeatedly declined to recuse himself from potential Justice Department investigations into Trump, his family and his aides – on anything from conflicts of interest to potential Russia connections. The incoming AG’s close personal and professional ties would raise questions about his willingness to challenge the president.

The Washington Post’s Breanne Deppisch contributed to this report.