This is short and graphical. You may have noticed that a surprising number of sitting Republican members of the house were in districts that voted for Clinton in the 2016 election. 23 of them. There are enough folks there to swing control of the chamber. In the context of the AHCA vote, only a few of them would need to flip to really change things.
Why do people split their tickets?
The most straightforward explanation would be that voters prefer divided government. Combine this preference with a hypertrophic sense of agency and you might be casting the ballot that produces a mixed government — after all every thing else is equal, right?
On the other hand, there is a body of research which would indicate that split tickets are a result of “blurry party identities.” If only this research could have been sustained — an environment where Bush and Gore blend would be far preferable to what we see now. For what it is worth, there are a fair number of districts that split for a democrat and Trump, like the Minnesota 7th — which aside from the 2016 cycle is a conservative, although not overwhelmingly conservative district. Other reasons aside from divided government would include personalities, local issues, or holding onto a prized position in the house.
What are some key features of this game?
Every voter is making a few decisions: President, Senate, House. For the purposes of this game we will focus on the House. In a world with budget reconciliation, the filibuster is already a dominated strategy. In the game you choose a President (Democrat or Republican) and a Representative (Democrat or Republican). Let’s start with the idea that people like divided government.
If you stay on the left side, you end up with democratic control, if you go right, republican. In this game there are four outcomes, two with party dominance and two with mixed governance.
A strategy that any voter should consider is backward induction, what would be the possible end points of their game. For this hypothetical person, DR is best, meaning Clinton+Issa — this is the scenario that played out in that district. Trump and the other challenger, and then Clinton and Challenger is third.
Taking account of dominated options
In game theory, when something is clearly not going to happen or a move is too bad to make, it is considered dominated and thus should be pruned from the game or strategy. In boxing, all strategies that do not include raise gloves for defensive posture are not worth considering as they result in a solid punch in the face.
When we think about the congressional game it is important to note that only about 30 seats are actually competitive, meaning less than a ten percent margin of victory. Gerrymandering, geography, the census, and a list of factors explain this. In short: if you have a ballot that actually decides something, you actually have some power. My ballot means little as the Oregon 4th is not exactly competitive.
If we made a tree diagram of the entire congressional game, only a handful of branches would avoid pruning. Since nearly the entire game is dominated it would only make sense that many people would not vote. Why would it matter?
Future: Party Governance
Ticket splitting is declining. Congress is becoming more partisan. Party identities are increasingly clear. The political Pareto distribution above doesn’t land you in the creamy middle of a negotiated equilibrium by magic, it conforms to how these processes actually work. Gravity pulls the parties and power toward the axes.
The system as we know it depends on those ovals meeting up. Today, they don’t. The ovals will move further apart. Since governance is no longer happening in that magical dashed oval all the games that took place there are now also dominated. Prestige and decorum games: throw them in the trash. The Republicans know this: there is no negotiation, no reasoning, no justification, not even real public relations. Why bother — none of these are directly tied to the process of securing the votes and once you have the votes you will always play the most aggressive strategy.
Unfortunately, the American system was designed assuming that the regions would cross and the negotiation would carry the day. Instead journalists and the public will continue to learn that so much of the system was cultural, not structural, and destroying culture can be a power move.