-
O'Brien has been working in the State Department as the administration's hostage negotiator. He'll replace former Ambassador John Bolton, who parted company with Trump.
-
The national security adviser caught the president's attention for his aggressive stance as a Fox News commentator but strayed from favor after pushing too hard against Trump's wishes.
-
According to inside accounts, the president and McMaster clashed when the top aide's cerebral briefings crashed into Trump's more freewheeling style.