Trump Names Bolton National Security Adviser03/23/2018 Charging ahead with the dramatic remaking of his White House, President Donald Trump said he would replace national security adviser H.R. McMaster with the former U.N. Ambassador John Bolton, a foreign policy hawk entering an administration facing key decisions on Iran and North Korea. After weeks of speculation about McMaster's future, Trump and the respected three-star general put a positive face on the Thursday departure, making no reference to the growing public friction between them. Trump tweeted that McMaster had done "an outstanding job & will always remain my friend." He said Bolton will take over April 9 as his third national security adviser in just over a year.