Cascades
One point of contention amongst oh so many in the recent Presidential Election was the viability of third parties. Some parties, notably the Libertarian and Green parties, did much better than is normal for a party outside of the major two; even within the Republican party we saw discord with the attempt of Evan McMullin in Utah. It’s easy to see why; both candidates for the two major parties set records in disapproval this election. Despite this, though, none of these parties saw anything close to real success. The Libertarian party did best¹, and still feel notably short of the meager 5% necessary to attend major debates. Why are these parties, even at their best, falling so incredibly short?
To summarize, they are failing to cascade amongst voters. It’s no secret that America has a winner-take-all system, which creates an interesting effect: voting for your preferred party often isn’t the right strategy. This means we can model voters as networks and parties as ideas in need of diffusion, as in Chapter 19 of the book. Sure, voting for, say, the Green party might be worth 10 points to you, but if you don’t know anyone else voting Green, it might seem wasteful. Perhaps, if you’re surrounded by Democrats, you vote that way just so that it counts for something.
The analogy isn’t perfect. In reality, people vote *against* just as often as *for*, and unlike perfect network nodes, different people have very different values for things. But the effects are similar, nonetheless. The cascade effect is preserved; the closer a party gets to 50% (or any plurality) of the vote, the more viable – and therefore attractive – they are. In other words, the more nodes relevant to you are voting for a party, the more value you get from doing so as well. This means that the network of voters looks very similar to diffusion networks – Large blocs of well-connected nodes that are hard to penetrate with new ideas. Both major parties hang around 50% of the votes, almost every election. Small groups, well connected in their own ways (the Libertarian party is almost universally young and male¹), hang outside on the fringes, failing to spread but maintaining cohesion. These demographic and cultural blocs act just like clusters, preventing the spread of a new party even if some members would prefer it in theory. Some argue that the external forces of the election format have been overwhelmed amongst ‘millennials’ – the cluster that notably formed the bulk for support for not only Gary Johnson and Jill Stein, in their parties, but Bernie Sanders, a Democrat but an outsider, in the primaries. Perhaps the millennial cluster, very tightly interconnected by the internet, has cascaded away from the rest of the network, and having done so will remain separate.
¹ http://www.nytimes.com/2016/09/05/us/politics/gary-johnson-libertarian-third-party.html