[EM] Weak Condorcet winners

[Jameson Quinn]

2011/9/23 James Gilmour <jgilmour at globalnet.co.uk>

> Warren Smith  > Sent: Friday, September 23, 2011 1:53 AM
> > At the present time, Jon Huntsman gets only a tiny
> > fraction of the USA-republican-presidential-nomination votes,
> > according to polls. For this reason, certain media people
> > have been saying it is a travesty Huntsman continues to run
> > and is allowed in debates, etc.
> >
> > However...
> > it is mathematically possible (and might even be true -- I
> > have no idea... it's at least somewhat plausible) that
> > Huntsman is "everybody's second choice" and therefore is the
> > Condorcet candidate who would defeat every Republican rival
> > one on one.
> >
> > So there's a possible very important example of a "weak
> > Condorcet winner" in your face right now.
>
> Your point is obscure.  My point is not that a "weak Condorcet winner"
> might exist or be elected, but about the political and
> Political consequences of such a result.  The electors may vote that way,
> but once they and the party politicians see what has
> happened all hell will break loose.  And it will be stirred up by a very
> hostile media.  At least, that's what I would confidently
> predict would happen here in the UK.  The "weak Condorcet winner", while
> being the Condorcet winner, would be totally ineffective in
> the discharge of the office to which s/he was elected.
>
>
Moreover, the very possibility that a given system might elect a weak CW,
will be used as an argument against adopting that system in the first place.
This argument will be especially convincing to officeholders, who would hate
to be defeated by a weak CW.

Note that a weak CW can win in non-Condorcet systems. In Approval, Range,
and MJ, a weak candidate can theoretically win even if they are not even a
CW; but the situation only becomes plausible if they are. In all three of
those systems, you could argue that this would probably be rare with
real-world voter behavior; but to my knowledge, only with MJ is there
published data to back this up.

Failing the majority criterion is, in my view, a similar flaw to electing a
weak CW. In both cases, it's at worst a "suprise" result that a majority of
voters easily could have and would have avoided if they'd realized it was
coming; and in both cases, it's a system flaw that will appear intolerable
to officeholders. Approval, Range, and MJ all fail the ranked MC; of them,
only MJ clearly passes the rated MC. Range's MC failure, in particular, is
often used as an argument against it; whether or not this argument is valid,
it seems to be telling.

Again, SODA is not subject to either a weak CW or a non-MC result. I
consider these flaws to be the biggest obstacles to system adoption; and the
chicken dilemma, also uniquely solved by SODA, to be probably the
most-common real-world hurdle for a good electoral system. I consider these
advantages to be important enough that theorists should seriously consider
SODA even if they have some objections to Asset-style systems. After all,
SODA's asset-like aspects are entirely optional for the voter.

Jameson
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