President Trump on Wednesday announced that Robert C. O’Brien will replace John Bolton, whom Trump fired last week, as his new national security adviser. O’Brien is currently serving as a special presidential envoy at the State Department working on releasing hostages. Trump tweeted: “I have worked long & hard with Robert. He will do a great job!” Notably, O’Brien was asked to help Trump in his pet project calling for the release of rapper A$AP Rocky from Sweden after he was arrested in the alleged assault of a Swedish man.