We knew that President Trump’s pick for attorney general had offered commentary that was suspiciously critical of the Justice Department’s treatment of Trump. We didn’t know nearly how far it went.

News broke Wednesday night that William Barr had written an unsolicited 20-page memo to DOJ arguing that special counsel Robert S. Mueller III’s obstruction of justice investigation was not just unwarranted but “grossly irresponsible,” “fatally misconceived” and carried “potentially disastrous implications.”

The former attorney general, who held that job in the George H.W. Bush administration, reportedly disclosed the memo to Trump after Trump nominated him for his old job, noting that it was likely to come up in his confirmation hearing.

The things Barr says in the memo are very much in line with other quotes that have surfaced. Barr has been a proponent of executive authority and said Trump did nothing wrong in firing FBI Director James B. Comey — perhaps the central event in the obstruction probe. He has also said there is more basis to investigate Bill and Hillary Clinton on Uranium One than there was to investigate the Trump campaign for possible collusion with Russia. He told reporters the Justice Department was “abdicating its responsibility” by not pursuing the Clintons more. He criticized Mueller’s team for its political contributions to Democrats.

All of these things are in line with what Trump himself has said — and suggest Barr would perhaps take a softer line when it comes to Mueller’s probe.

But the new memo takes things to a whole new level. The quotes described above were offered to reporters who inquired about various matters. Some of them are problematic if you’re concerned about the future of Mueller’s probe, but to this point he had never explicitly suggested Mueller’s probe was illegitimate. He just minimized it relative to the Clintons and seemed to prejudge one specific event. The Comey firing, after all, is now just one of many potentially significant events in the obstruction probe.

The memo was extremely detailed and — perhaps most importantly — unsolicited. Here was a man who went to the trouble of rhetorically dismantling one entire half of Mueller’s probe, of his own volition. And the language used is not muted. “Grossly irresponsible,” “fatally misconceived,” and “potentially disastrous implications” are the words of someone who feels strongly that this is a miscarriage of justice. They are the words of a zealot who would seem to do whatever was in his power to hamstring that portion of Mueller’s probe. After all Barr, in his own estimation, would be preventing a disaster for American government. Barr isn’t just saying Trump is innocent; he’s saying the entire underpinning of the investigation is wrong and perhaps illegal.

Expect this memo to be a central focus of Barr’s confirmation hearings — including questions about potential recusal. In his memo, Barr acknowledges that he’s “in the dark about many facts” of the investigation because he is not privy to them. He may simply argue that he’ll approach the Mueller probe with an open mind once he learns those facts.

But this memo makes it abundantly clear what his preconceived notions are, and they are that at least half of Mueller’s probe is something of a cancer within American government.