Former Attorney General Eric Holder wrote in a Washington Post op-ed that his successor, William Barr, is “unfit” to hold the position and that his comments “have been fundamentally inconsistent with his duty to the Constitution.”

Holder, who said he was “reluctant to publicly criticize (his) successors,” blasted Barr for contradicting the findings of the Inspector General report. Barr said the FBI may have acted in “bad faith,” by opening the Russia  probe, despite the report finding the investigation to be justified and not have any political bias.

“(It) was infuriating to watch him publicly undermine an independent inspector general report — based on an exhaustive review of the FBI’s conduct — using partisan talking points bearing no resemblance to the facts his own department has uncovered,” he wrote.

Holder, who served in the Obama administration from 2009 to 2015 also criticized Barr for comments he made last month at an event held by a conservative legal group, in which he affirmed his support of presidential power, bashed the resistance movement and mocked Senate democrats.

“To me, his attempts to vilify the President’s critics sounded more like the tactics of an unscrupulous criminal defense lawyer than a U.S. attorney general,” Holder wrote, adding that Barr “exposed himself as a partisan actor, not an impartial law enforcement official.”

Holder continued, “Virtually since the moment he took office, though, Barr’s words and actions have been fundamentally inconsistent with his duty to the Constitution, which is why I now fear that his conduct — running political interference for an increasingly lawless president will wreak lasting damage.”

Former Acting Attorney General Matthew Whitaker appeared on Fox & Friends to rebuke Holder’s op-ed, arguing that Holder was just as partisan as Barr appears to be.

“He has been effective,” Whitaker said of Holder. “But, he is a highly partisan person who, as attorney general, was there to protect [President] Obama and did all sorts of things to make sure that Obama was successful.”