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

[Kristofer Munsterhjelm]

On 2024-04-03 20:09, Closed Limelike Curves 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 – 5/5
> Bush – 0/5
> Nazi – 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 
> /dis/incentivized that it can be catastrophic.

I would expect that DMTCBR methods would pass (be unaffected by) this as 
long as there's a sincere CW.

Characterizing the Nash equilibria of DMTCBR/DMTBR/resistant set methods 
would be interesting, but it's not like I'm lacking in work already :-)

-km