Consensus, Condorcet(0), and Condorcet(1/2)

[Steve Eppley]

[A message I sent to EM was eaten when eskimo.com broke down last 
week.  Here's the gist of it, hastily rewritten.]

The discussion about using "1/2 votes against both" in pairwise 
methods led me to think about what it is that the method ought to be 
measuring, and ponder the following question:

Which of the following is the greater violation of democratic 
principle in a 2-candidate race:

1. Electing candidate A even though A lost to B (46 to 54).
2. Electing candidate A even though A lost to B (34 to 46, 
     with 20 who have no preference between them).

There's no clearcut answer, seems to me.  In case 1, A has a smaller
margin of defeat and more supporters than in case 2.  But in case 2
there are fewer voters who would be made unhappier by changing the 
result from B to A than in case 1.

Condorcet(0) implements the principle that case 1 would be a greater
violation of democracy.  It tries to minimize the number of squawking 
voters when breaking the circular tie.  I don't know what Condorcet(1/2) 
implements.

Consensus is another well-established system which pays more
attention to opposition than support.  In Consensus, a proposal
which is opposed by any voter fails, no matter how many support it:
a proposal with 1 aye and 99 who don't care will pass, but a proposal
with 99 ayes and 1 nay will fail. 

---Steve     (Steve Eppley    seppley at alumni.caltech.edu)