Washington CNN  — 

Former Attorney General Eric Holder believes William Barr is “unfit” to serve as the nation’s top law enforcement officer, writing in a Washington Post op-ed that recent controversial comments by his successor “have been fundamentally inconsistent with his duty to the Constitution.”

In the opinion piece published Wednesday night, Holder, who served in the Obama administration between 2009 and 2015, excoriated Barr for “a series of public statements and … actions that are so plainly ideological, so nakedly partisan and so deeply inappropriate” for an attorney general to make. He pointed to a number of recent headline-grabbing remarks by Barr, including his comments this week that the FBI may have acted in “bad faith” when it opened an investigation into the origins of the Russia probe despite the Justice Department’s inspector general report that said the bureau was justified in doing so.

“(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 said he was “reluctant to publicly criticize (his) successors,” also blasted Barr for comments he made last month at an event held by the Federalist Society, a conservative legal group, in which the attorney general affirmed his credentials as a staunch defender of presidential power, trashed the so-called 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 in his comments, Barr “exposed himself as a partisan actor, not an impartial law enforcement official.”

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

CNN has reached out to the Justice Department for comment.

The former attorney general also went after Barr for “bizarre” comments he made at an event last week about the need for people to show “respect and support” for law enforcement or they risk finding “themselves without the police protection they need.”

“It is antithetical to the most basic tenets of equality and justice, and it undermines the need for understanding between law enforcement and certain communities and flies in the face of everything the Justice Department stands for,” Holder wrote.

CNN’s Tammy Kupperman, David Shortell and Katelyn Polantz contributed to this report.