Keep your eye on John Bolton in 2018

Bolton visits the White House in October. Photo: Chip Somodevilla / Getty Images

John Bolton will be in the mix this year. The hawkish former UN ambassador — whose name I often hear mentioned when sources game out the next phase of Trump's national security team — launches on Thursday what he says will be a $1 million advertising campaign to support Kevin Nicholson in the Republican Senate primary in Wisconsin.

Why this matters: Bolton remains an influential, if controversial, voice in Republican foreign policy, advocating a tear-it-up position with the Iran nuclear deal and muscular military actions around the world.