2011/9/22 James Gilmour <[email protected]> > Jameson Quinn > Sent: Thursday, September 22, 2011 2:00 AM > > If I'm right, the claim is that voters, and especially > > politicians, are intuitively concerned with the possibility > > of someone winning with broad but shallow support. In > > Approval, Condorcet, Majority Judgment, or Range, a > > relatively-unknown centrist could theoretically win a contest > > against two high-profile ideologically-opposed candidates. > > The theory is that the electorate would be so polarized that > > everyone would explicitly prefer the centrist to the other > > extreme, but because the voters don't really expect the > > low-profile centrist to win, they might miss some important > > flaw in the centrist which actually makes her a poor winner. > > I cannot comment on the quoted remark (cut) that prompted your post and I > know nothing at all about the activities of anyone at > FairVote, but you have hit on a real problem in practical politics in your > comment above - the problem of the weak Condorcet > winner. This is a very real political problem, in terms of selling the > voting system to partisan politicians (who are opposed to > any reform) and to a sceptical public. >
Yes. I think that your term "weak Condorcet winner" is clearer than my terms "mushy centrist" or "unknown centrist". And I think that a lot of IRV supporters talk about LNH, is actually about this problem. > > For example, with 3 candidates and 100 voters (ignoring irritant > preferences) we could have: > 35 A>C > 34 B>C > 31 C > "C" is the Condorcet winner. Despite the inevitable howls from FPTP > supporters, I think we could sell such an outcome to the > electors. > > But suppose the votes had been (again ignoring irrelevant preferences): > 48 A>C > 47 B>C > 5 C > "C" is still the Condorcet winner - no question about that. But I doubt > whether anyone could successfully sell such a result to the > electorate, at least, not here in the UK. > > And I have severe doubts about how effective such a winner could be in > office. Quite apart from the sceptical electorate, the > politicians of Party A and of Party B would be hounding such an > office-holder daily. And the media would be no help - they would > just pour fuel on the flames. The result would be political chaos and > totally ineffective government. > > The flaw in IRV is that it can, sometimes, fail to elect the Condorcet > winner. But IRV avoids the "political" problem of the weak > Condorcet winner. I suspect that's why IRV has been accepted for many > public and semi-public elections despite the Condorcet flaw. > I agree. Let's look how susceptible the good systems are to this flaw: Approval: Theoretically susceptible. Depends on whether the typical voter will approve a candidate who is in between the two frontrunners. I personally am skeptical that this would be a practical problem, but can cite no direct evidence of that. Condorcet: Susceptible, especially in margins-based versions. Probably the least susceptible version is Condorcet-Approval(implicit); which, along with its simplicity, is the reason I favor this version. MJ: Theoretically susceptible, but there is evidence to believe that it is not in practice. If B+L's empirically-based simulations rerunning the 2007 French presidential elections are to be credited, MJ is the least centrist-biased of the good systems (but also less extremist-biased than IRV or Plurality). Range: Theoretically susceptible, even to the extent of violating the majority criterion. The fact that this is unlikely to be a practical problem is, in my opinion, not going to be enough to assuage voter fears about what can be portrayed as a serious flaw. SODA: Uniquely unsusceptible among good systems (susceptibility roughly on par with IRV). This is a primary reason I see SODA as the proposal with the best chance of practical implementation over the long term. Jameson
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