I don't mean to say that, with those methods, members of a mutual majority (MM) don't have any strategy incentive. There would be some Condorcet strategy incentives.
If it looks as if IRV would eliminate the CW, then the favored wing would have some incentive to use Condorcet offensive strategy against the CW, to produce a cycle rather than a CW. Then, when the count goes to IRV, the CW gets eliminated, and hir votes are transferred to the favored wing, because that's the CW-preferrers' 2nd ranked choicee on their ballots. That could cause the elections to effectively devolve to Condorcet-strategy elections. But it would backfire if the favored wing got eliminated first. Then their offensive strategy would elect the opposite wing. Additionally, in the next election, that favored wing would likely be the disfavored wing. Additionally, that offensive strategy could only work if its victims were trying help the perpetrators. How low is that? How likely does it sound--especially considering the effect on the mutual majority? For those reasons I don't consider it a problem. But couldn't those arguments be used to defend Condorcet against criticism of its offensive strategy possibilities? Sure, and I've used them. But the only offensive strategy that I consider a problem of Condorcet is its chicken dilemma defection. The Condorcet-IRV hybrids don't have a chicken dilemma. --------------------------------------- I'll refer collectively to Approval, and the strategically-similar methods Score, ICT and Symmetrical ICT, as "Approval etc." or "Approval&c". Under current conditions, as opposed to Green scenario conditions, Approval&c is the only class of voting systems that I recommend. When I said that the hybrids are my favorite methods for the Green scenario, I didn't mean to imply that there is a definite and obvious choice. All methods have some sort of disadvantage or drawback. In the Green scenario, that's true of IRV, the Condorcet-IRV hybrids, and Approval&c. I emphasize that all of these methods, including IRV would be excellent for the Green scenario, despite their drawbacks. IRV's drawback is that it imposes a favorite-burial incentive on the disfavored wing. And it could displease CW-preferrers for their CW to be eliminated. That could add up to a displeased majority that would have sufficient numbers to throw IRV out, as in Burllington. The Condorcet-IRV hybrids' drawback is the Condorcet offensive strategy, but I've told why I don't consider it a problem. Nevertheless, it means that the hybrids' success in use would depend on trust and co-operation to some degree. I feel that it's to a reasonable degree. Approval&c's drawback in the Green scenario is just that it doesn't have the other methods' automatic guaranteed election of a mutual-majority-preferred candidate, and CD compliance, and the strategy-free-ness that goes with those properties. It isn't that there's anything wrong with Approval&c, or that it has a problem. It's just that it doesn't being the tremendous strategic benefit of IRV and the hybrids. Michael Ossipoff ---- Election-Methods mailing list - see http://electorama.com/em for list info
