[EM] Weak Condorcet winners [was: FairVote are not the friendliest]

[robert bristow-johnson]

On 9/22/11 2:37 PM, Jameson Quinn wrote:
>
>
> 2011/9/22 robert bristow-johnson <rbj at audioimagination.com 
> <mailto:rbj at audioimagination.com>>
>
>     On 9/22/11 12:40 PM, James Gilmour wrote:
>
>         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.
>
>
>     i remember Rob Ritchie arguing this case to me in 2009 (why
>     "sometimes IRV is better than Condorcet").
>
>
>         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.
>
>
>     even though there were 48 voters who preferred C over B, 47 that
>     preferred C over A, along with the 5 that preferred C over both A
>     and B.
>
>     that does not appear to me to be such a bad result.
>
>
> That's debatable. It's possible that C did not get an appropriate 
> level of scrutiny from the voters; that if they'd looked more closely, 
> they would have found some serious flaw.

that is a different issue.  vetting the candidates is an issue of having 
an effective press and also of the opposing camps and other political 
action groups.  if there is a skeleton in C's closet, it should come out 
before the election whether Condorcet or FPTP is used.

but again, Jameson, consider the alternative: whenever you elect someone 
who is not the Condorcet winner (especially if the election method had a 
ranked-choice ballot, so there would be no question who the CW is), what 
you are doing is electing someone (A or B) when a majority of the 
electorate marked their ballot that they preferred some other specific 
candidate (namely C) over whomever you elected.  that's a fundamental 
problem, if majority rule and one-person-one-vote are the axiomatic 
governing principles.

you can call C a "weak candidate", but i would call this simply a "close 
election".  close elections often draw out pathologies.  the typical 
pathology of a FPTP spoiled election (like Nader in 2000) can only 
happen when the election is close between the top two candidates (if 
Gore had a stronger lead over Bush, Nader wouldn't have made any 
difference).  so to point to a close election and say that the winner is 
suspect is nothing new.

i do not see the closeness of the scenario above as a convincing 
argument that the single candidate who is preferred by a majority of 
voters to any other candidate propped up against him/her should not be 
elected to office in favor of one of those others so propped up.  it's 
like Barrabas and Jesus; we hold up Candidates A and C and ask the 
electorate "whom do you choose? A or C?" and the electorate responds 
(with a slim majority), "C!".  so should we ignore the electorate and 
elect A instead?  this happens again with B and C and the electorate 
again responds with "C".  *why* should either A or B be elected when 
that is the case?

-- 

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."