[EM] Is autodeterrence bad? (+STAR fails hyperchicken catastrophically)

[Toby Pereira]

 I think one problem of burial-resistant methods is that they assume the electorate are aware of the consequences of it and will act accordingly. I think it might be a bit optimistic to expect the average voter to behave any differently using any method that uses a specific ballot type. Using a ranked ballot, if A and B are the frontrunning candidates, then supporters of A might rank B bottom because it's the obvious thing to do (which has been pointed out on here before I believe). Do you think the adoption of a specific Condorcet method will prevent that? I'm not convinced.
Also, if there are two frontrunning candidates, A and B, it's quite likely anyway that supporters of A will see B as the worst candidate anyway, below the ones they know very little about. So it wouldn't really even be an act of burial, and therefore honest voting behaviour could cause a non-entity to win, because this is what burial-resistant methods do.
I've said this before, but possibly the best solution for a Condorcet method would to be to use rated ballots. In this case B is less likely to be buried by the A supporters, because they would be likely to score the non-entity candidates 0 as well.
Toby
    On Wednesday, 3 April 2024 at 19:09:50 BST, Closed Limelike Curves <closed.limelike.curves at gmail.com> wrote:  
 
 I think the EM mailing list made a wrong turn a while back in misunderstanding "autodeterrence" as a positive attribute of a voting system, which discourages burial. I'd like to put forth an argument (which I'm still somewhat hesitant about) that it's a very bad property. Given the chance, political machines are likely to reach out and grab this third rail as hard as they can, even if it's terrible for their constituents, because it maximizes their chances of election.
Start with a 2.5-candidate race between Gore, Bush, and a Nazi (who has a small, but slightly above zero, level of support). Gore doesn't know whether he or Bush is more popular in a runoff, but he's certain he and Bush will make it to the runoff with honest voting. However, he realizes he can use the Nazi as a bludgeon to increase his chances of winning. He tells his supporters to cast votes as follows:
Gore – 5/5Bush – 0/5Nazi – 4/5
Gore's hope is that the Nazi is polarizing enough to defeat Bush for second place with Gore's support (at which point he's a weak candidate in the runoff). Risky? Yes. But it's still plausibly strategic if you think Bush will back down.
But if Bush's faction thinks the same thing, the Nazi ends up winning.
STAR punishes burial by blowing up the country, creating an extremely high-stakes game of chicken (hyperchicken?). This game has a mixed Nash equilibrium that involves blowing up the country with some small (but positive) probability. The issue isn't that burial is incentivized; it's that it can work, but when it fails, it's so strongly disincentivized that it can be catastrophic.
This can be especially bad since incentives are even stronger for candidates and campaigns. Campaigns coordinate strategy; voters take cues from campaigns and political elites (which is why the two major-party nominees are always the top-2 winners).
The strategy above would be bad for society, and ambiguous for individual voters (it could elect either Gore or a Nazi). On the other hand, great for Gore's probability of winning, if Gore 
Empirically, this kind of turkey-raising happens all the time. Adam Schiff spent millions trying to boost the Republican in California over Katie Porter. The DNC keeps intervening in Republican primaries to help nominate extremists. They keep doing this because they think it's good for their own personal chances of winning the election, not because they think it's good for the country overall. And generally, they're right—even though it risks electing Nazis, it probably helps Democrats win a few more seats.
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