The key numbers for midterms are 35 and 15.

[Awsi Dooger]

2. I would be thrilled at 39 and 9

35 and 15 simply aren't realistic. Something would have to fall off the map, a worse scandal and stretch of news than anything Trump has managed so far. At 35 and 15 we would pick up far more than 20 House seats, and we would be favored to retake the senate instead of huge underdog.

At 42% approval now you are asking for 1 out of every 6 of them to change their minds. That is an incredible burden since so many of them are blind partisans. This is hardly a free flowing primary where impressions can shift based on one debate performance or gaffe. A very high percentage among that 42% are fine with Trump no matter what he says or does.

Truthfully, my 39 and 9 are probably unrealistic also, given so many data points toward the current 42 and 7. We are increasingly locked in place.

In looking at 538, the pollster YouGov accounts for a very high percentage of the polling they chart. Often YouGov is responsible for half of the Trump approval polls within a given stretch. It is a B rated pollster according to Nate Silver.

I keep thinking that the accuracy of Trump's approval number is largely dependent on YouGov's competence level during this cycle.