The move added to the list of actions by President Trump that use the powers of his office to weaken perceived enemies.
Federal worker unions have sought over the past two months to lead the resistance to President Trump and his Department of Government Efficiency, filing lawsuits, organizing protests and signing up new members by the thousands.
This week, Mr. Trump struck back with a potentially crippling blow.
In a sweeping executive order denouncing the unions as “hostile” to his agenda, the president cited national security concerns to remove some one million civil servants across more than a dozen agencies from the reach of organized labor, eliminating the unions’ power to represent those workers at the bargaining table or in court.
A lawsuit accompanying the executive order, filed by the administration in federal court in Texas, asks a judge to give the president permission to rescind collective bargaining agreements, citing national security interests and saying the agreements had “hamstrung” executive authority.
Labor leaders vowed on Friday to challenge the Trump actions in court. But, barring a legal intervention, the moves could kneecap federal unions and protections for many civil service employees just as workers brace for a new round of job cuts across the government.
“They are hobbling the union, ripping up collective bargaining agreements, and then they will come for the workers,” said Brian Kelly, a Michigan-based employee of the Environmental Protection Agency who heads a local of the American Federation of Government Employees, the country’s largest federal employee union. “So, it’s a worst-case scenario.”
The move added to the list of actions by Mr. Trump to use the levers of the presidency to weaken perceived enemies, in this case seeking to neutralize groups that represent civil servants who make up the “deep state” he is trying to dismantle. In issuing the order, Mr. Trump said he was using congressionally granted powers to designate certain sectors of the federal work force central to “national security missions,” and exempt from collective-bargaining requirements. Employees of some agencies, like the F.B.I. and the C.I.A., are already excluded from collective bargaining for these reasons.
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