Deputy Attorney General Rod Rosenstein and Solicitor General Noel Francisco weren’t the only ones keeping an eye on Jeff Sessions as the three indulged in a candle-lit moment of self-care away from President Donald Trump at an upscale Washington, D.C., restaurant on Wednesday night. Earlier that morning, Trump had fired off yet another cutting tweet at his beleaguered attorney general, calling Sessions “DISGRACEFUL” for not investigating the F.B.I. more forcefully over its surveillance of the Trump campaign. “Why is A.G. Jeff Sessions asking the Inspector General to investigate potentially massive FISA abuse. Will take forever, has no prosecutorial power and already late with reports on Comey etc. Isn’t the I.G. an Obama guy? Why not use Justice Department lawyers?” Sessions, in an extraordinary riposte, had pushed back at the president in a statement defending the Justice Department, fueling an already awkward feud between the two. The image that emerged afterward of Rosenstein, Francisco, and Sessions at dinner suggested a message of solidarity.

A third party is also deeply interested in the spat: Robert Mueller. The Washington Post reports that Trump’s public and private gripes about Sessions have drawn the attention of the special counsel, who is seeking to determine whether the president’s bullying behavior fits into a broader pattern of attempted obstruction of justice. According to the Post, Mueller is asking questions about a period last July during which Trump publicly attacked the D.O.J. chief on Twitter and declared that, if he could do it again, he would not have appointed him to the role. While The New York Times previously reported that the special counsel had been sniffing Trump’s efforts to prevent Sessions from recusing himself in the Russia probe, the latest news suggests that Mueller’s inquiry has broadened to include a wide range of interactions between the president and his attorney general. That focus likely includes the tweet Trump sent Wednesday, berating Sessions for not pushing to counter Mueller’s investigation, as well as his ongoing campaign to humiliate Sessions into resigning.

Trump has sought to push Sessions out since the attorney general recused himself from the F.B.I. Russia probe in March 2017, frustrated with what he views as a lack of loyalty from the man he reportedly calls “Mr. Magoo.” Ousting Sessions would be no easy matter, however. Firing the attorney general would likely be seen as further evidence of obstruction in the Russia probe, and could fuel calls for impeachment. Many lawmakers would be loath to confirm another attorney general under such circumstances. The Trump White House, meanwhile, has found it difficult to attract hires who are not only qualified, but who aren’t on the so-called “blacklist” of people who have insulted the president. Not only would Trump struggle to find a replacement who could pass the Senate’s muster, but Sessions has signaled on numerous occasions that he will not resign. (Trump, who turned “You’re fired” into his personal catchphrase on The Apprentice, is widely known to get cold feet when it comes to actually swinging the axe.)

As Sessions’s Wednesday night dinner neatly illustrated, any move against the attorney general would have also a domino effect inside the Justice Department. Trump has signaled that he has no trust in Rosenstein, the second in command at the department. The woman who would be third in line, Rachel Brand, resigned last month to take a high-powered job at Walmart. If Trump moved against Sessions and Rosenstein, the title of acting attorney general would next fall to Francisco—a cascade that would evoke Nixon’s infamous Saturday Night Massacre.

As Trump’s public castigations of Sessions picked up, lawmakers signaled that Trump would be crossing a line were he to fire the attorney general, a maneuver some feared would be the first step in shuttering Mueller’s probe. “Even people that disagree with him philosophically would not like the way that he was treated,” Trent Lott, the former Senate majority leader and whip, told me last year, adding that Sessions’s firing would not be “well-received.” Republicans rallied around the embattled D.O.J. on Wednesday as well, with Rep. Peter King noting that Sessions is “often in very difficult positions and I think he’s trying to reconcile as best as he can,” and Trey Gowdy, the chairman of the House Oversight Committee, professing to have “complete confidence” in inspector general Michael Horowitz.