Kevin Venzke wrote: > > --- Bart Ingles wrote: [...] > > I also have serious doubts about whole-vote ER-IRV, mainly over whether > > the Duvergerian equilibria would still be strong enough to maintain a > > two-party system. If so, then the differences between top-two, IRV, > > ER-IRV(fractional), ER-IRV(whole votes), or simply disqualifying all but > > the top-two primary winners from the general election, are largely > > academic, at least in U.S. partisan races. > > The difference between ER-IRV(whole) and those other methods is that the > voter can just submit an approval ballot if he wants. ER-IRV(whole) fails > FBC but not, I think, in a very predictable way. Other than this, there is > no incentive to raise compromises above preferred candidates. > > If this reasoning doesn't convince you, I'd like to ask what it is about > ER-IRV(whole) that you think would still maintain a two-party system.
I'm unconvinced because I don't believe that FBC failure is particularly rare. It seems to me that once you have identified the "lesser-evil" candidate best able to defeat the "greatest threat" candidate, optimal strategy would be the rank the lesser-evil first ahead of anyone else. I would only include my favorite in the top rank if I believed that my favorite was likely to beat all disliked candidates. But in that case, why rank anyone else first? Maybe for insurance, I suppose, but I think that ranking multiple candidates first would be fairly rare compared with approval voting. What would convince me otherwise would be a set of strategy equations comparable to those used for calculating optimal strategy in approval voting, or possibly simulations with ER-IRV(whole) showing that "lesser-evil or better" strategy is as good or better than "lesser-evil-only" in terms of social utility efficiency. Bart ---- Election-methods mailing list - see http://electorama.com/em for list info
