Re: Another proposal.
On Tue, Nov 19, 2002 at 01:53:46PM +1000, Anthony Towns wrote:
> What we'd like to do is something similar:
>
> * allow a pre-determined minority to block a vote.
>
> * allow them to express sincere preferences between options,
> without being forced to invoke their minority block, _or_
> being forced not to invoke their minority block.
Ok, I think I see your basic goal (which is rather subtle). But I
think you are misguided on how to achieve it. Below...
> > However, I don't see why you'd want to encourage insincere (ie,
> > strategic) voting, ever.
>
> I don't really think this is... meaningful. The default option isn't
> something you can be particularly "sincere" about
Your point here being that even if the default wins, the vote will
be held again, and little is lost. Yes?
So you think it's ok if the system allows you to be obstructionist.
I'll concede this. It's probably unavoidable, and may even be
desirable.
But, I still insist that it is still not ok if the system allows an
insincere vote to hand victory to a non-default option.
> The only real issue is the one where your sincere vote:
>
> A S D (normal option, supermajority option, default option)
>
> will cause S to win (thanks to you letting it pass its supermajority), but
> your insincere vote:
>
> A D S
>
> will cause A to win (thanks to S being eliminated early, by not passing its
> supermajority).
In this case, I think it would be fair for the insincere reversal to
casue D to win, thus sending the matter back to discussion. This
would not in fact be "strategy" in an voting sense, rather in a
larger political sense, and is thus outside the scope of a voting
system.
But causing A to win is not fair.
One supporting argument is that this strategy would still be
applicable without a supermajority requirement (assuming that
options beaten by the default are still eliminated early). My last
message had an example.
I think I could come up with more supporting arguments with more
time, but I have to go now.
> The only case in which that can happen is if you have a circular tie:
>
> S > A, A > D, D > S (scaled)
>
> But in that case, you're really just ending up with the same problems you get
> in ordinary Condorcet voting, where the circular tie:
Yes, strategy is possible in Condorcet. However, it is requires
very particular circumstances, and thus is probably unreliable in
practice. The CSSD tie-break method is designed so that even if you
can produce a circular tie (by reversing the result of one pairwise
contest), you probably won't change the final outcome.
With an "eliminate early" step, on the other hand, reversing the
result of one pairwise contest can reliably knock out one option.
This is unacceptible, IMO.
In short, I think the Condorcet method will achieve your goal of
allowing obstructionism just fine. Indeed, it is much closer to
your original example (voting against option A in a straight
"yeah"/"nay" vote, because you want to get the chance to vote on
option B) than "eliminate early". "Eliminate early" is a pure
distortion with no analog in traditional voting strategy.
I'm not sure I've phrased my argument well, but I hope you will
think some more about whether what you said you want, is really what
you want. As I said, it's subtle.
Andrew
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