The Trump administration-appointed head of a key advisory council on the civil service has resigned over an executive order to strip away protections against political interference in hiring and firing for a large portion of the career federal workforce.

The order, which could affect tens of thousands or more career positions involved in making or carrying out policy, “is nothing more than a smoke screen for what is clearly an attempt to require the political loyalty of those who advise the President, or failing that, to enable their removal with little if any due process,” Ronald Sanders wrote in his letter of resignation Sunday from the Federal Salary Council.

“I simply cannot be part of an Administration that seeks . . . to replace apolitical expertise with political obeisance. Career Federal employees are legally and duty-bound to be nonpartisan; they take an oath to preserve and protect our Constitution and the rule of law . . . not to be loyal to a particular President or Administration,” he wrote.

Sanders has served in federal personnel positions across four decades, starting as a local labor relations officer for management and then holding senior positions at the Defense Department, the Internal Revenue Service, the Office of Personnel Management and in the intelligence community, among other roles.

Now the director of the School of Public Affairs at the University of South Florida, Sanders was appointed in 2018 to head the salary council, which oversees an annual comparison of federal vs. private-sector salaries and the locality-based pay system for a large majority of the 2.1 million executive branch employees.

His resignation comes just days after the latest annual meeting of the council, where Sanders argued for what he called the management point of view on several issues, including granting higher pay to federal employees working in certain areas. He also again questioned the methods the council uses in determining the “pay gap” with the private sector, which showed federal employees behind by 23 percent on average.

However, later that day, President Trump issued an executive order to redesignate career employees in “confidential, policy-determining, policymaking, and policy-advocating positions” as falling under rules that primarily apply to political appointees. Such “excepted service” positions do not require competition in hiring, or even public notice that a position is available, do not allow for union representation and do not allow for appeals of disciplinary actions, including firing.

Under the order, agencies are to conduct an initial review within three months, and a full review within seven months, of such positions. The OPM then would change their status, affecting both current and future employees. It is uncertain whether any could or would be changed before the first deadline, which falls just before Inauguration Day in January.

The White House released a statement Monday that did not directly address Sanders’s letter. “It should surprise no one that President Trump is increasing accountability in Washington,” the statement said. “This much-needed reform will improve the effectiveness of the federal government in essential policy-making positions.”

In resigning, Sanders said that although he is a lifelong Republican, he “cannot in good conscience continue” to serve the administration. Trump’s order “seeks to make loyalty to him the litmus test for many thousands of career civil servants, and that is something I cannot be part of.”

In a phone interview, Sanders said the order was “flagrantly different” from other administration initiatives he opposed, such as moving civil service policy directly under the White House — a plan that Congress last year blocked pending a study.

“I don’t want to sound too corny here, but it was just a matter of conscience,” Sanders said. “When I saw that [order] and I did some soul-searching, I just don’t want to be a part of it, that’s all.”

Rep. Don Beyer (D-Va.) called Sanders’s resignation “unfortunate but honorable.”

“Everyone should be outraged by Trump’s radical attack on the federal workforce, which seeks to take America’s civil service back 137 years to a time when political loyalty was deemed more important than merit or skill,” he said in a statement.

Top officials of two of the largest employee unions also supported Sanders’s decision to resign. “Americans should be extremely concerned about a president who wants to replace professionalism and merit with political loyalty, who wants decisions based on ideology rather than facts, and who undermines trust in our government agencies to further a political agenda,” Tony Reardon, president of National Treasury Employees Union, said in a statement.

Jacqueline Simon, a member of the salary council who often clashed with Sanders over policy matters, said: “It’s extremely late in the day to do the right thing, but he’s doing the right thing.”

“This executive order was somehow either a last straw or a bridge too far,” Simon, public policy director of the American Federation of Government Employees, said in a phone interview. “I think it’s the worst thing Trump has done on the civil service.”