Though he won’t start in his new job for several weeks, John Bolton — who will replace Gen. H.R. McMaster in the role of National Security Advisor, President Donald Trump announced on Thursday — isn’t exactly an unknown quantity when it comes to his views on diplomacy and security. The ambassador, also a regular Fox News presence, has been a polarizing public figure in American international relations for more than a decade, and behind the scenes for even longer. Notably, Bolton worked as under secretary of state for arms control and international security under President George W.