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.

President Donald Trump says protecting national security gives him the authority to end collective bargaining with labor unions across most of the federal government

Donald Trump’s administration moved to invalidate contracts between a swath of US government agencies and the largest federal union representing their employees, marking a sweeping attack on collective bargaining rights as the president aims to lay off government workers.