OK, the presidential election is looking like positions are solidifying. Back in April, I posted that the Clinton-Trump campaign would be entertaining but meaningless. We would see a bloodbath on the way to a predetermined endpoint. At this point, it looks like the the underlying conditions slightly favor Republicans, but Trump is just such an awful candidate that opinions of him are baked in, and it would take a dramatic external event to shift things in his favor. Absent that, Clinton wins.
So, let's talk about Congress.
The House goes GOP. We'll get to the Senate, but let's have a brief lesson on why the House goes so reliably GOP these days. It ain't what you think. Scary word that gets misused and mispronounced: "gerrymandering." (Properly pronounced with a hard "g," if you want to sound like a proper, pompous ass). No, the House doesn't go GOP because Republican state legislatures have gerrymandered everything in an elaborate scheme.
Here's the real deal. Democrats cluster in cities. That means Democratic-leaning regions are more heavily Democratic than Republican-leaning regions. So, it is very easy to draw an 80-20 Democratic district. It is much harder to draw an 80-20 Republican district. How do you draw the former? Make it an urban district. How do you draw the latter? Uh, make it Utah. (Where Trump might lose!)
Now, what does that mean? Getting a partisan advantage in the redistricting process is all about spreading your voters out more efficiently than the other party. If my districts are 60-40 majority districts, and the other party's districts are 70-30 majority districts, then I win more seats because I can spread my voters out among more districts. The catch is that if you have a majority too slim, there's a risk. A slight shift, and you lose the district.
If you want the math, I wrote a paper on it. Here's a link. Basically, you are safe for the census cycle once you hit around 65% within a district, and in a state with around 20 districts, if you have a 55-45 overall advantage, that means you can give yourself a 75-25 advantage in seats.
Underlying all of this, though, is basic demography. Democrats cluster in cities. Republicans spread themselves out more efficiently in suburbs. In order to draw district lines that don't advantage Republicans, then, you have to go out of your way to chop up cities.
Can that be done? Sure, but unless lines are drawn in an intentional way to chop up cities, combining the urban centers with the suburbs and rural areas to balance out the urban clusters of Democrats with the outlying Republicans, then Republicans have a built-in advantage.
It wasn't always that way. Back when the South voted for Democrats, particularly those with names like "Phil Gramm" until 1983, Democrats had a lock on the House. But, things change. Since 1994, there were only two elections in which Democrats won the House: 2006 and 2008. One was the midterm backlash against a Republican president during the worst days of the Iraq War, and the other was in the midst of the financial collapse.
Republicans will win the House. And Republican state legislatures don't need to do much besides not chop up cities to keep it that way, and even Trump can't help the Democrats much there.
The Senate? Well...