"This idea that an incumbent has to win a primary challenge by 20 points or he is in trouble is nonsense."
I didn't say that. What I was trying to say was that any incumbent who is otherwise popular with the base should win any Primary by closer to 50 points, or he is in trouble.
That simply is not true. I don't care who the incumbent is if there is a primary challenger there will be no 20 point win. Too many "base" folks are anti-incumbent on general principle.