Yes Trump's Approval Rating Is Up, No That Doesn't Mean the Democrats Won't Succeed in November

Trump's approval rating has clearly gone up in the last month, from a little under 40 percent to a little under 42 percent, according to the 538 composite. That's not nothing and, all else equal, good for the Republicans. But it doesn't change much about expectations for the upcoming election, which are still quite poor for the GOP.

Models, of course, disagree on how grim the forecast is for the Republicans, so any given model should not be taken as the last word. But Seth Masket at Mischiefs of Faction cites a midterm model that illustrates how difficult the situation is for them. The model is a simple one that relies on just Presidential approval and growth in real per capita disposable income (RDI). What it says is this:

[The model] predicts Democrats will pick up 45 to 50 House seats this fall, and take over 15 to 20 state legislative chambers. A loss of just 24 House seats would flip House control to the Democrats….

Most years, this model works fairly well. It predicted Democrats losing 46 House seats in 2010 (they lost 63), and it predicted Republicans losing 40 House seats in 2006 (they lost 31).

You can see in the chart above how this works, with Trump's approval running a little over 40 percent and RDI growth around 1 percent in the last year. It's apparent that moving Trump's approval rating around a little bit at a given level of economic growth does not change the forecast much. Plus Trump's approval rating have been bouncing around between 37 and 42 percent since early last April  so it's hard to see the kind of mega-spike that might really change things. 

A huge increase in RDI growth seems unlikely also though, of course, anything is possible. But as Masket observes: 

Even if RDI growth jumped to 3 percent…the model would still predict Republicans to lose 37 House seats, more than enough to lose control of the chamber, and 14 state legislative chambers.

So the fundamentals don't look good for Team Red. But it's just one model so should be treated with caution. After all, there are lots of other factors like the various structural advantages Republicans take into an election like this. But even those have been declining as Nate Cohn has pointed out, knocking a couple of points off of the GOP's "thumb on the scales". This includes the effects of anti-gerrymandering court decisions, Democratic fundraising and candidate recruitment and Republican retirements.

It's a long time 'til election day. But the basic story continues to be a positive one for Democrats, as these data and the results of recent special elections suggest.