Key points
- A shift from first-past-the-post to PR shifts party competition from being within parties to being between parties. It is not clear that this is good.
- Under PR you get more parties. This includes far right parties. There is a significant advantage in future electoral competition once you've become an established party.
- Coalitions have the problem of it being hard for voters to hold specific parties or leaders to account for policies.
- Coalitions create a free rider problem because the reputation of the coalition government is a public good.
- The median voter theorem no longer holds. If voters have extremist tendencies there is no competitive pressure not to serve them
- Italian and French politics look not good. Having non FPTP seems plausible to have played a part in this in that it allowed Front National to gain a significant foothold in France while no equivalent far right party has sprung up in the UK. The Northern League is not fascist but is hard right and is currently the largest party in the Italian Parliament. The Brothers of Italy are literally neo-fascists and have been part of Italian coalition government and plausibly could be again.
- Big tent Social democrats competing with Christian Democrats seemed to work fine.
My claim isn't that first past the post is clearly better than other electoral systems, but it's not clearly much worse and so I wouldn't expect it to pass the very high bar of being an EA cause area.
An important point note is that these arguments apply much less strongly to the US because of the much weaker parties.
I may or may not write a more detailed account of this, but given my record of trying and failing to write good forum posts, this may the best I'll do.
I think using Bayesian regret misses a number of important things.
It's somewhat unclear if it means utility in the sense of a function that maps preference relations to real numbers, or utility in axiological sense. If it's in the former sense then I think it misses a number of very important things. The first is that preferences are changed by the political process. The second is that people have stable preferences for terrible things like capital punishment.
If it means it in the axiological sense then I don't think we have strong reason to believe that how people vote will be closely related and I think we have reason to believe it will be different systematically. This also makes it vulnerable to some people having terrible outcomes.
Lots of what I'm worried about with elected leaders are negative externalities. For instance, quite plausibly the main reasons Trump was bad was his opposition to climate change and rejecting democratic norms. The former harms mostly people in other countries and future generations, and the latter mostly future generations (and probably people in other countries too more than Americans although it's not obviously true.)
It also doesn't account for dynamic affects of parties changing their platforms. My claim is that the overton window is real and important.
I think that having strong political parties which the electoral system protects is good for stopping these things in rich democracies because I think the gatekeepers will systematically support the system that put them in power. I also think the set of polices the elite support is better in the axiological sense than those supported by the voting population. The catch here is that the US has weak political parties that are supported by electoral system.