It is not clear where Trump got the idea that Horowitz, known as an even-handed professional among current and former Justice Department employees, would deliberately weaken the report. Horowitz served as a prosecutor in the office of the U.S. Attorney for the Southern District of New York, and in the Justice Department’s criminal division, and was appointed to the inspector general’s job in 2012 by former President Barack Obama.

“Horowitz is an extremely experienced and capable lawyer and former prosecutor,” said David Kris, a founder of Culper Partners who served as the assistant attorney general for the DOJ’s National Security Division from 2009 to 2011.

Horowitz’s power is fairly limited—in a noncriminal review such as the one Horowitz has been conducting into the FBI’s conduct, the inspector general’s office cannot compel testimony from former or non-DOJ employees, for example.* “While current employees have to cooperate with the investigation or face discipline, employees who have left DOJ can refuse to talk, as can everyone else who does not work for DOJ. That makes this kind of review far less authoritative than a criminal investigation,” said William Yeomans, a former deputy assistant attorney general who spent 26 years at the DOJ. “The standards for including something in an IG report are lower than that for proving a fact in a criminal case. I also know from personal experience that the IG gets facts wrong sometimes.”

A spokesman for the OIG declined to comment on the record.

Even so, the IG’s findings and recommendations are broadly viewed as credible by DOJ leadership, and will inevitably be leveraged by Trump and his allies in their efforts to undermine Comey, who was fired by Trump last May and subsequently became an important witness in Special Counsel Robert Mueller’s probe. In addition to investigating Russian interference in the 2016 presidential election, Mueller is looking at whether Trump attempted to obstruct the Russia inquiry.

“The IG has considerable discretion in making recommendations,” Yeomans said. “There are times when management disagrees with the IG’s recommendations and it can disregard them, but it’s safe to assume (or has been in the past) that Congress will expect an explanation for why a significant recommendation was not followed.” The DOJ, moreover, has historically taken the inspector general’s work “very seriously,” said Kris, the former assistant attorney general. He pointed to the reforms made a decade ago following the IG’s report on the FBI’s use of national-security letters.

Matthew Miller, a former Justice Department spokesman who served under Attorney General Eric Holder, agreed that the inspector general’s findings “are taken incredibly seriously by DOJ leadership, even when they disagree with the findings, as they occasionally do.” He noted that attorneys general and FBI directors will “often” implement new policies or reforms “in direct reaction to things the IG uncovered, as well as discipline people who are found to have engaged in wrongdoing. For better or worse, the IG is usually the final word on what happened, who was at fault, and what needs to be done to fix things when there is a DOJ scandal.”