With Michael Flynn resigning the post after a few weeks, and Vice Admiral Robert Harward turning the position down, the Trump Administration has settled on Lt. Gen. H.R. McMaster as their latest National Security Adviser, something of a surprise as he was not widely reported as among the front-runners.
The most prominent front-runner in recent days was ultra-hawk John Bolton, who the Trump Administration ultimately decided against, but who Trump insists will still be given some position of import in the future.
McMaster's primary claim to fame is the 1997 book Dereliction of Duty, in which he details the failures of the Vietnam War, and argues that the military leadership had failed to communicate to Defense Secretary Robert McNamara that his strategy was failing. He goes on to argue that military actions intended to show American "resolve" tend to fail if they lack concrete military objectives.