[EM] Strategic voting in Condorcet & Range N-canddt elections

[Kevin Venzke]

Hi Warren,

--- En date de : Mar 9.6.09, Warren Smith <warren.wds at gmail.com> a écrit :
> >> 5. In a monotone Condorcet method (such as
> Schulze, Tideman
> > ranked
> > pairs, etc) you cannot go wrong by ranking A top and
> B
> > bottom (both of
> > which, in general, will be dishonest, but this is
> always
> > strategically
> > correct).
> 
> >Venzke: What assumptions are you making? This doesn't
> seem to be demonstrated.
> 
> --it is just the monotonicity and the asumption only A
> & B can win.
> 
> If you think some other vote is more strategic, then fine,
> use it,
> then I will raise A to top, which never hurts me due to
> monotonicity
> assumption, and drop B to bottom, same argument, thus
> proving my vote
> is at least as strategic as yours.
> 
> So for the rest let us assume voters will cast votes with
> A,B top &
> bottom (or reverse)
> only, due to them being strategically wise and also due to
> them
> wanting to simplify
> their lives if they can (and they can, here).

But the "strategically wise" characterization, as well as the assumption
that only A or B can win, go out the window as soon as neither A nor B
has an outright majority. This happens already in Plurality elections.
I am pretty sure that third party supporters will analyze this situation
and find that the odds of C>A>B votes creating a harmful cycle are small
compared to the odds of C being the (voted) Condorcet winner.

Kevin Venzke