An executive order signed by the president would cancel collective bargaining for hundreds of thousands of workers, the largest federal employees union said. The union was preparing legal action.

The White House cited national security concerns for terminating workers’ ability to bargain collectively, but the order applies at agencies with both direct and indirect links to national security.

President Trump's new executive order ends collective bargaining for wide swaths of federal employees, as part of his broader campaign to reshape the government's workforce. Unions vow to sue.