James Green-Armytage wrote:
I do believe that Condorcet wv had a serious strategy problem.
This problem is in no way limited to winning votes Condorcet. The exact same strategy works in margins Condorcet. Furthermore (and, in my opinion, more importantly), the same effect can often be achieved in margins Condorcet by simply truncating your ballot. Simple truncation can only very rarely help your cause in winning votes condorcet, but it can help in common situations in margins Condorcet.
While it is unknown how likely a successful execution of the burial strategy would be in a public election, I believe that if it did occur, it would produce an *extremely* negative reaction towards both the result and the election method itself.
I agree, however, I see it as extremely unlikely that burial strategy would be successful on a large scale without public coordination, which would be easy to counter and would create a big scandal.
Remember that there are lots of people who have a sense of obligation that pushes them towards voting sincerely.
Is an example just like this very likely? No, I guess it's probably
pretty unlikely. (However, I think that there are other kinds of examples
where successful burying strategies are a bit easier and more plausible...
I think that I've provided some of these examples already...) But anyway
it is *possible*, and the possibility of such a disaster justifies at
least one more balloting.
And yes, Mike, I *do* think that just one more balloting in the event of
a majority rule cycle would be a great help.
Let me put it this way: Without a second balloting, I would not
necessarily feel comfortable about recommending Condorcet for public
elections instead of something like IRV.
Not because IRV is a good election method (it isn't, really), or because
the Condorcet principle is unimportant (I think that it's extremely
important), but because a successful burial strategy or an out-of-control
chicken game in single-balloting Condorcet would just undermine the
democratic process too severely, and I wouldn't feel comfortable in
opening up the possibility for that.
No such chicken game exists. If this strategy is pursued, there are successful potential counter-strategies that do not produce worse outcomes for the voters that take them. In your example, the Nader voters can rank Nader and Kerry equally. Given the large sincere Bush>Nader majority that is unaffected by the burial strategy, this costs them nothing.
With a second balloting, I would say that Condorcet is vastly superior to
IRV and pretty much any other public election method around.
What if no candidate is willing to drop out?
The thing is, the people who would be employing the "countermeasure" will
not know whether the strategy they are attempting to counter has taken
place, until after the election!
As I said before, in my opinion, for this strategy to work it would have to be very public.
And of course, at that point, it's very much too late to change whether or
not you truncated.
As you know, there are various examples where if voters truncate against
a strategic threat that in fact does not exist to begin with, it can
result in the election of the car crash candidate in itself.
Not in any example you've provided. As I said, the Nader=Kerry>Bush vote is basically a freebie.
So voters can't always take lightly the decision to truncate against a candidate who may or may not be supported by strategic buryers.
You need to provide an example where this is true.
What it may come down to is: To what extent do voters on each side have a
propensity to gamble with burial strategies? To what extent do voters on
each side expect voters on the other side to engage in burial strategies.
You need to provide an example where this is true.
I think that in a two-round procedure, candidate withdrawal would play a
more important role in effectively neutralizing strategy. The best way to
assure that no abuses would be effective in the second round would be for
a set of candidates to come to some sort of agreement whereby all but one
of them drop out of the race before the second balloting, so that the
opposition would not be able to use one of them to 'impale' the other one
with a huge artificial defeat and leave the legitimate defeat of their own
candidate as the defeat of least magnitude. There is still plenty of
opportunity for cooperation to break down during the negotiation stage
here, but at least it isn't possible for a strategic maneuver to steal the
election completely by surprise, as it is in the single-balloting version.
Again, what if nobody wants to drop out? Or what if a new burial strategy emerges in the second round? I don't see the 2-round election as a reliable solution to this "problem".
-Adam
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