[EM] Composite methods (Re: Eric Maskin promotes the Black method)

[Kristofer Munsterhjelm]

Juho Laatu wrote:
> On 8.7.2011, at 11.00, Kristofer Munsterhjelm wrote:
> 
>> But now consider a parallel universe where the CW always won (and
>> these victories were significant, i.e. people really preferred the
>> CW to the rest). Say Montroll won. Then Kiss-supporters and
>> Wright-supporters might try to unite in the feeling that Montroll
>> wasn't what they wanted ("we don't want any steenkin centrists");
>> but if they tried so, there would be a majority who did like
>> Montroll (because he was the CW), and therefore these could block
>> the repeal if it came to a referendum.
> 
> Condorcet methods are majority oriented, but unfortunately CW has
> majority only in pairwise comparisons. Majority of the voters would
> choose the centrist rather than X. But it is possible that majority
> of that majority would want Y rather than the centrist. And quite
> typically majority of the voters prefer someone else to the CW.

My point is that a majority of a majority isn't enough in a 
repeal-or-not referendum. If the repeal side can gather only a majority 
of a majority, while the keep-it side can gather a full majority, the 
method remains.

> In a two-party oriented political system both major parties would
> prefer a centrist to the candidate of the other major party. But if
> they think carefully, maybe it would after all be in their interest
> to just accept the fact that the major parties rule each 50% of the
> time, instead of e.g. the centrists ruling 50% of the time, leaving
> 25% to each of the major parties.

The more general concept that you mention is of course true. I was 
considering Condorcet methods as new methods versus other methods as new 
methods, and giving a possibility that Condorcet methods might outlast 
non-Condorcet methods in voting reform.

If society didn't have any bias at all, and could coordinate, it would 
quickly converge to the method that would do it best. The society would 
say "We don't like the spoiler effect, let's find a way to fix it". But 
because voting reform is hard, we can assume that doesn't hold true.

So yes, voting reform will be hard, no matter what new method you want 
to put in place. I'm merely saying that because of dynamics, it might be 
easier to replace status quo with a Condorcet method (and have the new 
method last) than it is to do so with a non-Condorcet method (and have 
*it* last), because majorities can complain more often in the latter 
case than in the former.

If people are in favor of two-party rule, well, then Plurality will 
remain. If they want two-party rule with no chance of minor spoilers 
upsetting the outcome, they may settle on IRV. But even here, Condorcet 
wouldn't be worse than IRV: if the voters want two parties, then one 
would assume they'd vote in a manner consistent with it. Third parties 
wouldn't break free -- because the voters don't want them -- and a 
cloneproof Condorcet method would keep minor spoilers out of the way.