Read: The inadvisable president

That drily delivered answer contains a great deal of meat. It’s impossible to read his statements about rule of law and the “independence and reputation” of the Justice Department as anything other than an implicit rebuke of Trump, who has tried to railroad the department into prosecuting political adversaries and overriding ethical recommendations; of former Attorney General Jeff Sessions, who resisted Trump’s biggest pressures but saw DOJ take a steep decline in esteem; and of Matt Whitaker, the political apparatchik who’s now the acting attorney general.

Barr came across, during the hearing, as the sort of Washington figure who holds a near-religious reverence for the Justice Department. Not only did Barr previously serve as attorney general, late in George H. W. Bush’s presidency, but he also has a long list of relations who work or have worked at the department—as well as an 8-year-old grandson who, he quipped, “will someday be in the Department of Justice.”

Barr’s veneration for the DOJ seems to be a powerful force in his desire to take the job again. He may also nurse the same ambition as many people who have held powerful jobs: the desire to hold them again. Being attorney general is a plum position, and whatever caveats might apply in the Trump administration, people want Cabinet roles.

Barr’s paeans to the rule of law and independence of the Justice Department also suggest he might feel some of the same sense of duty to protect the country from Trump that compelled Mattis to serve, despite his misgivings. Perhaps Barr harbors dreams of being a modern-day Elliot Richardson, the attorney general who stood up to Richard Nixon and resigned rather than fire Special Prosecutor Archibald Cox. Barr did tell senators he’d resign before doing something illegal, but the prospect of martyrdom is an unlikely reason to take a job.

Like Mattis, Barr shows little evidence of being a real Trumpist. His interest in the rule of law is enough evidence of that, as is his service to Bush, a president with few if any similarities to Trump. Barr is a conservative Republican in the old mold, but Trump is not. On Tuesday, Barr praised Mueller as a man of impeccable integrity and said the special counsel would not take part in a witch hunt (though Barr allowed that Trump might feel persecuted, since he is the one under investigation).

The one exception in Barr’s recent past is the unsolicited memo that he submitted to Deputy Attorney General Rod Rosenstein criticizing one interpretation of the law on obstruction of justice, related to the Mueller probe. Barr tried to write the memo off as a speculative interpretation based on little real knowledge of Mueller’s view of obstruction of justice—as though his input carried only the weight of an obscure legal blogger and not a former attorney general.