A career civil servant who claimed retribution by the Trump administration after speaking out as a whistleblower resigned from his post on Wednesday, citing poor leadership and wasteful spending as the factors that drove him out.

Joel Clement was one of dozens of Senior Executive Service employees reassigned to different jobs at the Interior Department a few months after Secretary Ryan Zinke was sworn in, a move Clement claimed was in response to his public warnings of the impact of climate change on Native Alaskans. After serving just a few months in his new position in the Office of Natural Resources Revenue, Clement sent a letter to Zinke announcing his resignation and faulting the secretary for “disrespecting the career staff of the department.”

“I’m proud to have served at DOI alongside such devoted public servants, and I share their dedication to the mission and country,” Clement wrote, “so it is with a heavy heart that I am resigning as a senior official at the department.”

The now former career senior executive said Zinke and the Trump administration have demonstrated poor leadership at Interior by waging an “all-out assault on the civil service by muzzling scientists and policy experts like myself.” He made several criticisms of the administration’s policy and regulatory rollbacks, which he said Zinke pursued to “score points with your political base at the expense of American health and safety.”

Removing him from a position for which he was qualified to one that required an entirely new skillset, Clement said, was a waste of the department’s resources. Interior recently sent him to Colorado for training for his new job.

“Reassigning and training me as an auditor when I have no background in that field will involve an exorbitant amount of time and effort on the part of my colleagues, incur significant taxpayer expense and create a situation in which these talented specialists are being led by someone without experience in their field,” Clement wrote. “I choose to save them the trouble, save taxpayer dollars, and honor the organization by stepping away to find a role more suited to my skills.”

Finally, Clement cited Zinke’s unwillingness to “lead on climate change” as a motivation for pushing him out the door.

“If the Trump administration continues to try to silence experts in science, health and other fields,” Clement said, “many more Americans, and the natural ecosystems upon which they depend, will be put at risk.”

Clement has filed a whistleblower complaint with Office of Special Counsel, which the watchdog agency is currently reviewing. The former executive made a name for himself by writing an op-ed in July in The Washington Post that sounded the alarm on his reassignment and the alleged retaliation. His reassignment has prompted bipartisan concern on Capitol Hill and outcry from legal scholars. Interior has reassigned about 50 of its senior executives, about one-fifth of those it employs. The department has claimed the transfers were designed to “better serve the taxpayer and the department’s operations.” Clement served as the director of the Office of Policy Analysis at Interior before moving to his new job.

In June testimony before the Senate Appropriations Committee, Interior Secretary Ryan Zinke told lawmakers he planned to shed 4,000 employees through “a combination of attrition, reassignments and separation incentives.” To Clement, that amounted to an open admission Interior had reassigned him in hopes that he would simply quit. Zinke went on to say at the hearing, however, that the Senior Executive Service “by definition gets moved.”

Clement told Government Executive he struggled with giving the administration what he perceived as their goal from the outset, but ultimately decided he could do more good if he left.

“Their intent in my view was clearly to get me to quit,” he said. “On the one hand I don’t want to give them what they want, but I can be much more effective in pushing back on their agenda from the outside.” He added: “I was more worried about losing my voice than my job.”

He said he does not yet know his plans for what he will do next, but he ultimately reached a breaking point in which he could no longer work for a department as its leadership attempted to tear down its mission. While he decided to leave, he encouraged his colleagues to stick around at Interior.

“My thoughts and wishes are with the career women and men who remain at DOI,” Clement said in his letter. “I encourage them to persist when possible, resist when necessary, and speak truth to power so the institution may recover and thrive once this assault on its mission is over.”