Sean Spicer’s resignation, on Friday morning, after six months of routinely lying from the White House lectern and then ending on-camera briefings altogether, once again raises one of the most important questions of the Trump era: What is the red line that Trump must cross for his aides to quit on principle? For Spicer, the answer was a new boss he didn’t like. Trump, over the objections of Spicer and Spicer’s closest White House ally, Reince Priebus, the President’s chief of staff, hired Anthony Scaramucci, a New York financier and frequent Trump surrogate on TV, as his new White House communications director.

The hire is unusual for several reasons. The role of communications director, a job that has been vacant since May, when Michael Dubke, a low-key Republican strategist, resigned from the position, is traditionally reserved for campaign operatives. Scaramucci is a Wall Street guy—he started at Goldman Sachs and later founded his own investment firms—and a former host on the Fox Business channel. Before the Trump campaign, his experience in politics was more on the fund-raising side than on the strategy side. In the Trump campaign, which was small, he took on a broader role as an adviser to the candidate and appeared frequently on TV, where he stood out because he was less ideological than the usual pro-Trump pundits.

More unusual is the way Scaramucci was hired. In a normal White House, the chief of staff is in charge of hiring. For the President to overrule his chief of staff on such an important position is an enormous embarrassment for Priebus. During a briefing on Friday afternoon, Scaramucci tried to downplay the friction between him and Priebus, but for months he has been telling people of his frustrations with the chief of staff. Scaramucci was originally asked to run the White House Office of Intergovernmental Affairs, but Priebus blocked Scaramucci from taking the job, even after Scaramucci sold his investment firm to take it.

Scaramucci then appealed directly to Trump to find him another position. He had three meetings scheduled with the President, and they were all cancelled. Scaramucci believed that Priebus, who is in charge of Trump’s schedule, worked to keep him away from Trump. Scaramucci “had to go over the top and directly to the President,” a source familiar with the episode said. “The problem is that Trump is in such a bubble now, he doesn’t know what the hell is going on.” Scaramucci was offered the ambassadorship to the Organization for Economic Cooperation and Development, in Europe.

If Priebus thought he had rid the White House of Scaramucci, he was wrong. In recent weeks, Scaramucci was a familiar figure at the Trump Hotel in Washington, meeting with reporters and Trump advisers. Ostensibly, he was there because he was working as an official at the D.C.-based Export-Import Bank. But, clearly, something else was in the works.

For Spicer, Trump’s decision to install Scaramucci above him—the press secretary reports to the communications director—was too much to take. Given the highs and lows of Spicer’s time at the White House, this was an unusual choice of hills to die on. Spicer began his tenure as press secretary with a bizarre rant about how Trump’s Inauguration audience “was the largest audience to ever witness an Inauguration, period.” (It wasn’t.) For someone who was never fully inside the Trump circle of trust, the performance had the ring of an eager gang initiate committing a crime to please the boss. Trump, who regularly watched the briefings, which were broadcast live on cable news, reportedly complained about Spicer’s pale suits and later seemed to become aggravated that Spicer was becoming famous, or at least infamous. Spicer’s temper tantrums, ill-fitting suits, and mispronunciations turned him into a pop-culture sensation.

But it was Spicer’s lies and defense of lies that he will be remembered for. Spicer defended Trump’s lie about how there were three million fraudulent votes in the 2016 election. He spent weeks using shifting stories to defend Trump’s lie about President Barack Obama wiretapping Trump Tower. In trying to explain the urgency of the attack on Syria, Spicer explained, “You had someone as despicable as Hitler, who didn’t even sink to using chemical weapons.”

Last week, he lied about the nature of the meeting at Trump Tower in June, 2016, between senior Trump-campaign officials and several people claiming to have information about Hillary Clinton from the Russian government. “There was nothing, as far as we know, that would lead anyone to believe that there was anything except for discussion about adoption,” Spicer claimed, bizarrely, because Donald Trump, Jr., had already admitted that the meeting was about Russian dirt on Clinton. On March 10th, Spicer came to the lectern wearing an upside-down American flag, which is a signal of dire distress.

Despite the repeated humiliations of standing before reporters and saying things he had to know were untrue, what finally made working at the White House intolerable for Spicer was a minor staffing issue. Scaramucci comes to his new job with a good reputation. He is not a conservative ideologue—he is pro-choice, a moderate on gun control, and anti-death penalty—and he is well-liked by reporters. But working for Trump can have a corrosive effect on good people. Scaramucci’s task is to, without sacrificing his own reputation, communicate on behalf of a President who routinely lies. Scaramucci has his work cut out for him.