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(CNN) —  

An FBI special agent says he’s turned in his badge so he can publicly voice his concerns over the politicization of the bureau by Republicans in Congress and the Trump administration.

“FBI agents are dogged people who do not care about the direction of political winds,” former FBI special agent Josh Campbell, who was announced Monday as a CNN law enforcement analyst, wrote in a New York Times op-ed. “But to succeed in their work, they need public backing. Scorched-earth attacks from politicians with partisan goals now threaten that support, raising corrosive doubts about the integrity of the FBI that could last for generations.”

The op-ed comes amid Republicans’ increased scrutiny of the Justice Department and the FBI for their handling of the Russia investigation.

Campbell’s piece was published Friday, the same day the Trump administration published an intelligence memo compiled by House Intelligence Committee Republicans that alleges FBI and Justice Department abuses of the Foreign Intelligence Surveillance Act. The memo accuses the FBI of improperly using information paid for in part by Hillary Clinton’s campaign to obtain a FISA warrant for Trump campaign foreign policy adviser Carter Page.

Democrats have blasted the memo as a misleading document that omits key facts about the Page FISA application, accusing Republicans of using the memo to try to undermine special counsel Robert Mueller’s probe.

The FBI said in a statement prior to the memo’s publication that it had “grave concerns” about the memo’s accuracy.

President Donald Trump has said the memo “totally vindicates” him in the Russia probe.

Campbell said he believes “political operatives are weaponizing their disagreement” with the Russia investigation “in a bid to undermine the credibility of the entire institution” of the FBI, which could tarnish the public support of federal law enforcement for years to come.

“The assumption among confused and dismayed FBI employees is that the attacks are meant to soften the blow should the investigation by Mr. Mueller, the special counsel, lead to additional charges. However, these kinds of attacks by powerful people go beyond mere criticism — they could destroy the institution,” Campbell wrote.

Campbell served as a special assistant to former FBI Director James Comey, who Trump fired last year.

Comey dismissed any significance to the memo when it was published, and on Friday tweeted that Campbell “will be missed at the FBI, but his voice is an important addition to the national conversation.”

CNN’s Jeremy Herb contributed to this report