The structure survived during the early part of Trump’s presidency, when the office was headed by Rear Adm. Timothy Ziemer. But, after John Bolton became Trump’s third national security adviser, he decided the organizational chart was a mess and led to too many conflicts. He also thought the staff was too large, having swollen to 430 people, including staffers in the pipeline.
Bolton fired Tom Bossert, the homeland security adviser, realigning the post to report directly to him. He eliminated a number of deputy national security advisers so there was just one. And he folded the global health directorate into a new one that focused on counterproliferation and biodefense.