My guess is that POTUS is about 5% responsible for executing The Plan. MI worked on this for years prior to approaching Mr. Trump and asking him to participate.
As much as I admire and respect Mr. Trump for leaving his cushy lifestyle and taking all these slings and arrows, I (optimistically) believe that once The Plan was set in motion, no single person or entity will be able to stop it.
As I recall, it was "A/B or C".
I took it to mean, "Either kill yourself or we will hang you for treason, OR turn yourself in and work for us".
I think they were either on a different island or part of an island that was upwind of any nuclear fallout when the small nuke was successfully intercepted. This would have provided all of them plausible deniability for a clown-backed NK attack on their own country.