I don’t agree with this, either.Either way I think it’s clear that the normal rules don’t apply to this guy electorally.
He remains historically popular with his own party, but not because his party can’t be drawn away from him. Instead, the Republican Party has lost 10% of its membership in the last two years. His behavior is so isolating that frustrated conservatives no longer recognize the party that some worked for, for their entire lives.
If America was 100 people, 25 of them would currently be Republicans, of which 24 would view him favorably. Of the other 75 people, only 14 or so would have a favorable opinion. Those 14 would mostly fall under “tepid support.“ Meanwhile, the entire rest of the population has a vastly disproportionate passionate dislike.
His party has suffered in every single special election since he arrived, not always losing but never managing remotely healthy numbers. Republicans in office are retiring in record numbers in part because of the internal polling they have access to. All of this in spite of a solid economy and the fact that the most watched news channel in America has openly turned itself into a propaganda machine specifically for him. Every topic he touches changes the narrative in the opposite direction. Immigration, the ACA, and abortion all have record levels of support right now, apparently resultant purely from his standing against them.
I don’t see any metric by which Donald Trump appears to be anything but a drag on his party, and his own potential for success.