[EM] IRV vs Plurality

[Abd ul-Rahman Lomax]

At 07:22 PM 1/25/2010, Juho wrote:

>There are many (working) uses for an approval cutoff in ranked
>ballots. But on the other hand they may add complexity and confusion
>and not add anything essential. => Careful consideration needed.

Only a voting systems theorist who is not a parliamentarian or 
familiar with the principles of parliamentary traditions, essential 
in direct democracy, would think approval not relevant. Approval is 
Yes/No on the series of possible choices. It's fundamental, actually, 
and compromises with this are *never* made in direct democracies, 
they are only made in the name of efficiency in large-scale elections.

>>Bucklin does that, basically, by only considering approval votes,
>>but it sets up a declining approval cutoff, typically in three
>>batches, loosely named as Favorite, Preferred, and Approved. I've
>>suggested that in a runoff voting situation, majority required,
>>"Approved" has a very specific meaning: it means "I would prefer to
>>see this candidate elected over holding a runoff election." Voters,
>>then, by what candidates they choose to approve given their overall
>>understanding of election possibilities, will sincerely vote this.
>>It makes no sense not to.
>
>Bucklin is a bit simpler.

Simpler than what? The proposed method? Sure.

>>By definition, range methods put extra weight on first preferences,
>>if the voter chooses to express the first preference exclusively, as
>>does Bucklin, at least in the first round.
>
>Range is also designed to elect candidates with no core support, e.g.
>one that gets 60% of the points from all voters while all others have
>only limited amount of strong support and no support from the rest.
>IRV puts always main weight on first preferences (among the remaining
>candidates).

Yes. However, "designed to elect candidates with no core support" is 
an overstatement. It certainly is not designed for that, but it 
allows it. It's pretty unlikely, eh? The most common response to this 
claim when it comes from FairVote is,"Really, even the candidate and 
her mother prefer someone else?" And when there really is a problem 
with core support, it comes down to, usually, center squeeze, and the 
compromise winner is, in fact, quite strong in first preference 
votes, but merely ends up, in a three-way race, in third place, and 
not by a large margin. Not at all "no core support."

Appeasing the "core support criterion" is a very bad idea, rewarding 
partisan affiliation without sound reason for it; the only arguments 
I've seen for it that carry any weight are arguments that core 
support is necessary for good governance, which is not entirely 
incorrect, but which doesn't counterbalance the danger of serious 
social division. Remember that the Nazi Party in Germany had "core 
support." Mmmm, did that help them govern? Sure it did! But "good 
governance"? No, not at all, I certainly hope we will agree. Any core 
support criterion pushes results away from true majority-supported 
results toward domination by the largest faction. Which, of course, 
then encourages a two-party system, at best.