I assume it will be challenged in court. Here is the meat:

The U.S. Office of Personnel Management, which oversees the federal workforce, issued a final rule on Thursday that creates a category of worker for high-ranking career employees whose work focuses on executing the administration’s policies. Workers who fall into that category would no longer be subject to rules that for decades have set a high bar for firing federal employees.
While political appointees at agencies are considered at-will employees who serve at the discretion of the president, career employees have long enjoyed strong job protections, including the ability to appeal firings, suspensions, or disciplinary action to an independent board. Workers that fall under the new category wouldn’t be able to appeal to the board.

Are these people unionized?