That refers to the Dobbs/Falwell interview as the original source material. Falwell is speculating, based on a call "something strange is going on, they are meeting frequently, and Trump will not be the nominee on November 8," combined with the observation all of us can make about which elected officials have said "he won't be the nominee."
A good part of the plot is out in the open, elected officials signing onto "No Trump" letters, for example.
