The White House cited national security concerns for an executive order that represents a major expansion of its efforts to shrink the government.

President Donald Trump is trying to revoke collective bargaining rights from most federal employees — the latest move in his aggressive campaign to weaken the federal workforce. Trump issued an executive order late Thursday night relying on a rarely used provision of the federal labor laws that authorizes the president to exclude agencies from long-standing unionization rights if he determines that those agencies are primarily engaged in national security work.