I think people look at the "presidents who lose get primaried" dataset (Johnson, Carter, H.W.) and draw the wrong conclusions. 1/
Aside from the obvious problems with the very small dataset, getting primaried itself isn't the problem. Nixon had two credible primary challengers: McCloskey from the left and Ashbrook from the right. 2/
Neither caught fire, because Nixon was in remarkably good shape (which reminds us how quickly things can change). In other words, a strong primary challenge is a *symptom*, not a disease itself. 3/
Presidents who lose draw strong primary challenges because they are weak enough that there is discontent within the base, and not the other way around. 4/
Of course, Trump getting a low score in NH would show evidence that he is weak, but we already know this without looking at primary results. 5/5
