[EM] Postscript, July 4 comments

[John B. Hodges]

I wrote:
So, basically what you have shown with this example [the IRV 
nightmare scenario] is that pure center parties can get squeezed out 
under IRV. To remain viable, a pure center party has to stay larger 
than at least one wing, taken as a coalition. It has to poach voters 
from at least one wing; it cannot allow itself passively to be 
poached upon. In trying to poach from either wing it may lose some 
voters to the opposite wing; probably the equilibrium solution 
involves two parties glaring at each other over the 50-yard line, 
each fighting also to guard their rear from additional parties. 
"Wing" parties may win if Center-wing and Wing together make a 
majority but Center-wing allows itself to get too centrist. There 
will always be at least two distinctly different parties.

Postscript: It occurs to me that there may BE no equilibrium 
solution. Because IRV essentially eliminates the spoiler effect, it 
greatly reduces the effective "barriers to entry" of new parties. So 
the field is always competitive; every party has to work to keep its' 
voters, it can take no voters for granted. Every voter is a "swing" 
voter.

In a one-dimensional "left-right" analysis, all we can say is that 
under IRV the voters on the "50-yard line" will always be part of the 
final winning coalition. (The center-voters will always prefer the 
final winner to all its remaining competitors, a trivial result for a 
majoritarian system.) We cannot say that any PARTY will always be 
part of the winning coalition. Speaking as a voter, this is IMHO a 
good feature.

Enough for today; got a party to go to, to celebrate our 
anti-imperialist Revolution.
-- 
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John B. Hodges, jbhodges@   @usit.net
The two-party system is obsolete and dysfunctional.
Better forms of democracy: www.fairvote.org
REAL CHOICES, NEW VOICES, by Douglas J. Amy