From the outside, it has been the strangest selection process of any of the cabinet picks. It seems there have been two distorting forces: 1) Rudy Giuliani bizarrely decided he wanted State rather than something he was truly qualified for and given Rudy’s loyal service, Trump was reluctant to tell him “no”; 2) Trump took a liking to Mitt Romney, who is anathema to many of Trump’s supporters.
Now, Rudy is out and reportedly the stock of dark horse candidate Rex Tillerson, head of Exxon-Mobil, is on the rise. Tillerson has done lots of work in foreign countries, but he is really no more obviously suited for this job than Giuliani.
The natural pick here has always been John Bolton, who endorsed Trump early, who fits broadly within the Trump worldview that you might characterize as muscular realism, and actually has substantial foreign policy experience.