US President Donald Trump has replaced Rex Tillerson with Mike Pompeo as secretary of state, and US Army Lieutenant-General H.R. McMaster with John Bolton as national security adviser. These moves reflect the president’s desire to take firmer control of his administration’s foreign policy by populating his team with officials more in line with his own thinking and removing obstacles to his imposing his will. Like Trump, both Pompeo and Bolton are hawkish primacists, whereas Tillerson and McMaster were, broadly speaking, moderate realists. In Bolton’s case, Trump has appointed a man with a similarly impetuous and explosive temperament. Neither Secretary of Defense James Mattis nor White House Chief of Staff John Kelly, both retired four-star Marine generals, approved of the choice. Pompeo, for his part, is an ideologue and Trump loyalist who never appeared very comfortable in his relatively quiet role of director of the CIA.