[EM] Re: IRV letter

[Bart Ingles]

Chris Benham wrote:
> 
> IRV  meets  Mutual Majority (what Woodall calls "Majority"). It implies
>  Majority Favourite and Condorcet Loser (which of course
> implies Majority Loser).

Can someone tell me whether the following hypothetical method meets
Mutual Majority?

1. Voters submit ranked ballots.
2. While no surviving candidate has a top-choice majority:
      Eliminate the candidate with the greatest plurality of
first-choice votes.
(End definition)

Example:
3  A > B > C
49 B > C > A
48 C > B > A

Round 1: No candidate has 50% + 1, so B is eliminated.
Round 2: C wins with a 97% 'majority'.

The method does appear to meet Majority Favorite and Condorcet Loser.

> Part of the definition of  democracy is majority rule. If, for whatever
> reason, the political landscape remains dominated by two very
> large parties that get lots of  sincere first preference votes, and so
> are widely accepted as the only competive, legitimate contenders
> for  the single-winner offices; then it is very important  that the one
> which is preferred by a majority over the other  is the winner.

This is merely an assertion, and not one that I buy, although I probably
would have a few years ago.  Nevertheless...

> That is what the Majority criterion guarantees and is all about.

If I understand you correctly, it appears that neither Majority Favorite
nor Mutual Majority guarantees this (see above example).


> Another line of  arguement I could take is that  I know  from living in
> Australia all my life that IRV in practice is far from disastrous,
> so a cautious approach is to ask ourselves what are the most important
>  good qualities of  IRV  and  then make sure  we keep
> them.

It may be that in Australia, keeping IRV until a definite improvement is
agreed upon is the cautious approach.  But IRV is not yet entrenched in
the U.S.


> Bart later wrote (Mon.Apr.25):
> 
> >If the two-party system weren't propped up by an anti-competitive voting
> >system, I believe that this would change.  There is no evidence that it
> >EVER would under IRV, in which case I would just  as soon stay with
> >Plurality for partisan elections.
> >
> I could argue that IRV in Australia has helped lead to STV-PR being used
> in parts of it, and that has somewhat weakened the
> two-party system. Bart's  arguement seems to be premised on the belief
>  that any  3-party system is better than any 2-party
> system,  and that all 2-party systems are equally bad. I  might concede
> that IRV shares with Plurality the tendency to perpetuate
> a 2-party system, but I strongly maintain that it  makes for a much
> BETTER two-party system.

If STV in Australia's upper house has weakened the two-party system in
the lower house, I haven't seen much evidence of it.  The "out" parties
may receive more first-choice votes under IRV than they would under
plurality, but I don't view this as any more significant than
pre-election poll results in the U.S. (where third-party candidates
routinely poll higher than they do in the actual election). 

I never argued for a 3-party system.  What I favor is fair and open
competition among any number of parties, which I believe would make a
huge difference over any entrenched 2-party (or 1-party or 3-party)
system.

I argue that plurality makes for the better 2-party system, although I
suspect that it makes very little difference one way or the other.


> For one thing, there is less of the big two staying the big two just
> because everyone thinks they are. Without the Plurality split-vote
> problem, this bluff will be called more often and better. Both the big
> two have to be more responsive to the voters  to stay on top,
> and  it should be easier for one of them to be supplanted. Then there is
> the idea that small parties will become more visible, and this
> will help create demand for  PR.

I don't follow the first point.  I don't see any evidence that big
parties would have to be more responsive, although it may depend on
which voters you have in mind.  It seems to me that with two major
parties under IRV, the candidates can safely ignore all but the center
'swing' voters.  It may be that under a majoritarian system, the two
parties in power would become even more indistinguishable from one
another than they are under Plurality.

Since I am basically neutral regarding PR, the "IRV promotes STV"
argument means nothing to me.


> Bart again:
> 
> >But even when IRV chooses the Condorcet winner, it's apt to be an
> >artifical one, achieved by eliminating any possible independent
> >Condorcet winners before the ballots are even printed.  You might as
> >well outlaw third-party candidates altogether, so that you can guarantee
> >a majority-favorite winner regardless of the method used.
> >
> I have almost no idea what he is talking about here. The last sentence
> seems ridiculous. If you don't allow  third-party candidates
> to run, how do you know which is the "third-party"?

My point was that if you were to designate the Republicans and
Democrats, say, as the officially sanctioned parties, there would be no
problem with 'spoilers'.  This is effectively what IRV would do.  In
either case, the winner would always be the Condorcet winner, but the
term would be meaningless.


> >I no longer view third-party candidates as automatic spoilers.  With a
> >healthy mix of 3rd-party and independent candidates competing for
> >dissatisfied voters, neither of the major parties is a net long-term
> >beneficiary of a "spoiler effect".  Instead, 3rd-party predation will
> >tend to draw voters away from the more lackluster of the top-two, thus
> >tipping the balance in favor of the Social Utility winner.
> >
> So if  Bush wins because the "Left" vote is split, does that make him
> the  "Social Utility winner"??

More accurately the reverse-- if Bush is the S.U. winner, the 'Right'
vote is less likely to split than the Left.


> It is almost irrelevant  that neither major party is a  "net long-term
> beneficiary of  a  'spoiler effect'".

Well, I never argued that Plurality is the ideal system.  But I've come
to view runoffs as possibly equally bad in the opposite direction-- that
the proposed cure is as bad as the disease.


> The point is to pick the correct winner (at least in "two-party
> preferred" terms, to use the Australian term) in the short term.

Again back to your majoritarian assertion.  This is YOUR definition of
"correct", not a universally agreed-upon principle.  

Bart Ingles