[EM] STV - the transferrable part is OK (fair), the sequential round elimination is not

[Juho]

On Nov 3, 2009, at 5:27 PM, Kristofer Munsterhjelm wrote:

> Juho wrote:
>> If one really wants a two-party system and doesn't want voters to  
>> change that fact then one could ban third parties and accept only  
>> two. That would solve the spoiler problem :-).
> Who is this "one"? Since that one is at odds with the voters, that's  
> not very democratic, is it?

I was thinking about the voters or their representatives who want to  
have a two-party system. Those groups can be considered to be the key  
decision makers in a democratic system.

>
> I guess that one "democratic" way of doing it would be to have the  
> question itself posed to the voters, but with a suitable low-pass  
> filter (e.g. supermajority required to change it, or a majority over  
> a long time); though then I think it'd be better just to have the  
> filter on the decision process itself.

This is a good definition of democracy. I tend to think that if the  
voters have the opportunity to change any old rule if they really so  
want, then that society can be called democratic. (Also the two-party  
status (=one current practice of decision making) can be a topic to be  
changed.)

>
>> From this point of view e.g. the US system is not really intended to
>> be a two-party system but just a system (target state unspecified)
>> that has some problems with third parties.
>
> That's most likely the case. AFAIK, the founding fathers just copied  
> Britain's election methods (first past the post, etc.), and by the  
> time parts of the US noticed this wasn't really optimal, those who  
> benefitted from said methods' unfairness had acquired enough power  
> to block the adoption of better methods (e.g. the red scare campaign  
> leading to STV's repeal in New York).

One old proverb says that people tend to get the kind of government  
that they deserve. If people want change in a democratic system they  
should 1) understand and 2) act/decide.

>
> There are some exceptions. To my knowledge, some state governors are  
> elected by runoff rather than just "winner takes it all". FPTP  
> runoff may fail (such as with Le Pen in France, or more relevant -  
> the "better a lizard than a wizard" second round in Louisiana), but  
> at least it can't elect the Condorcet loser, which plain old FPTP  
> has no problem doing.

The Le Pen case was maybe not a full failure. Although it was shocking  
to many that a candidate that large majority of the voters definitely  
didn't want to elect got to the second round he was not elected anyway.

(Btw, I think it is ok to elect the Condorcet loser in some extreme  
situations. If for example the target is to elect a candidate that  
would be stable in the sense that there is no major interest to  
replace her soon after the election with some other candidate then  
Condorcet loser can be a better candidate than any of a badly looped  
Smith set. Group opinions are not linear and therefore the fact that  
one of the candidates seems to be "last" can not be automatically  
taken as a conclusion that some other candidate should win.)

Juho


>
>> On  the other hand the option of third parties could be left in the  
>> rules
>> intentionally. The voters are given a chance to change one of the  
>> two parties to some third party if they want that so much that  
>> despite of the associated spoiler problems they will eventually  
>> give the third party enough votes to beat one of the leading  
>> parties. Actually two-party systems need not be based on two  
>> parties only nation wide. In principle each district could have its  
>> own two parties that are independent of what the two parties are in  
>> other districts. There is however some tendency to end up with two  
>> or small number of parties nation wide.
>
> As another reply mentioned, this has happened in Canada. With very  
> local exceptions, it hasn't happened in the US - at least not  
> recently. I think a key difference is that the large US parties can  
> gerrymander, whereas that is not the case in Canada (since Elections  
> Canada does the redistricting there). When parties can pick their  
> constituents before the constituents can pick their representatives,  
> competition suffers because third parties can't get off the ground.