President Trump’s pick for attorney general, William Barr, was critical of the Mueller investigation in a memo to the Justice Department earlier this year, describing the inquiry into possible obstruction of justice by the president “fatally misconceived,” the Wall Street Journal reported Wednesday. In the June 8th memo, Barr couched his thoughts as a “former official” whose “views may be useful,” but, now, as the former attorney general at the tail end of the George H.W. Bush presidency is set to again take over the Justice Department, and likely the Mueller investigation as well, those views could decide the future course of the Russia investigation.

The 20-page document, the Journal notes, is the first look into Barr’s thinking on the most important and controversial decision he’ll likely make as attorney general—the future of the Mueller investigation. In the memo, Barr admits he’s “in the dark about many facts”—Mueller has not provided much information about the direction of the investigation—but goes on to assail Mueller’s legal reasoning as “grossly irresponsible” with “potentially disastrous implications” for the executive. “Barr argued in the memo that a president can be accused of obstructing justice under the relevant legal provision if he knowingly destroyed evidence or encouraged a witness to lie,” according to the Journal. “But Mr. Trump was lawfully exercising his authority in firing Mr. Comey, he wrote. If prosecutors pursue Mr. Trump over his comments to Mr. Comey about Mr. Flynn, according to the memo, it opens the door for every decision that is alleged to be improperly motivated to be investigated as ‘potential criminal obstruction.’”

Barr’s memo was sent to Deputy Attorney General Rod Rosenstein and Steven Engel, head of the Justice Department’s Office of Legal Counsel, but the pair did not circulate the memo widely nor share it with Trump or Mueller, according to the Journal’s reporting. The fact that Trump wasn’t aware of the memo when selecting Barr—though Barr says he mentioned it after being offered the job—will likely help the president get his attorney general confirmed by calming fears he was using potential hires’ views on Mueller as a litmus test for the next leader of the DOJ.