[EM] Conceiving a Democratic Electoral Process

[Kristofer Munsterhjelm]

On 07/13/2012 05:30 PM, Fred Gohlke wrote:
> Good Morning, Dave
>
> re: "Clones are a problem for Plurality, and primaries were
> invented to dispose of clones within a party"
>
> I'm not sure what clones are, but imagine they are multiple candidates
> who seek the same office.

Strictly speaking, clones are candidates that are so alike each other 
that every voter ranks them next to each other (but not necessarily in 
the same order). A method passes the independence of clones criterion if 
adding or removing clones never alters who wins - unless the winner was 
cloned (in which case one of the clones may win) or the winner was one 
of the clones removed (in which case a remaining clone may win).

Plurality fails the independence of clones criterion because splitting a 
candidate into clones can make them lose (vote-splitting). Borda fails 
it because splitting a candidate into clones can make one of the clones 
win (teaming). Copeland fails because adding or removing clones of some 
candidate A can make the win go from B to C (crowding).

More generally speaking, a clone could be considered a candidate that's 
very close to an already existing candidate and whose presence changes 
who wins.