the No Spoiling criterion

[Steve Eppley]

We've emphasized method criteria from the perspective of the voters
being able to elect the "best" of the available candidates.  Only
occasionally have we considered methods' effects on whether
potential candidates will choose not to run.

Why did Pat Buchanan ultimately decide to support Dole instead of 
running independently?  Why did Jesse Jackson decide to support 
Clinton instead of running himself?  Because of the spoiler dilemma,
which is the flip side of the LOE dilemma.

Here's a general and somewhat vague statement of a "no spoiler"
property which good election methods should have:  

    If candidate X would be elected when Y is not a candidate, 
    then X or Y will be elected if Y is a candidate (assuming 
    the voters don't alter their relative orderings of the 
    non-Y candidates).

As with the LOE criteria, it may take awhile to find a wording which 
can be rigorously met by at least one voting method.

Being the flip side of LOE, I'm pretty sure that methods will
satisify the No Spoiler criterion if and only if they satisfy the
LOE criterion.  

Here's a variant of the ubiquitous example:

    46:  Z > X
    54:  X > Z
      ==> X wins.
  -----------------
    46:  Z > X
    20:  X > Z
    34:  Y > X > Z
      ==> ??
      If the method is IR, Z wins.  IR violates No Spoiler.
      If the method is Condorcet, X wins.  Is there a bad example
      for Condorcet?

This criterion is just as vital to democracy.  The current vote-for-
one single-winner method forces groups to "unite" behind what they
hope is a candidate capable of both winning a plurality and inspiring
their coalition.  But a lot of human labor is wasted in this
organizational overhead, the guesses about which potential candidate
is their best champion are often wrong (e.g., the voters in primaries
are the ones most motivated to vote--the most progressive of the
Dems, the most conservative of the Reps, etc.) or distorted (e.g.,
early money, early endorsements) by the process, and the compromise
champion invariably fails to inspire a sizable fraction of the 
potential volunteer and voter turnout.

Single-winner methods which satisfy No Spoiler will allow groups to
avoid wasting their time organizing a huge coalition in support of a
single compromise champion.  The winning coalition will be an ad hoc
election day coalition, not a pre-election coalition.

Methods which satisfy No Spoiler will allow the big parties
to fragment into smaller ones and make primary elections less
essential.  Parties would still have to figure out how to allocate
their financial and labor resources effectively (and this might mean
using primaries to make those decisions) but they'd no longer have 
to treat voters as a resource which can only be allocated to one
candidate. 

If the Democrats and Republicans really fragment as a result of
better single-winner methods used to elect Senators and Housefolk
(and perhaps the President too), then the resulting multiparty
Congress would be much more interested in fixing the clause in the
Voting Rights Act of 1965 which, instead of mandating prop rep for
House elections, made prop rep House elections illegal.  

It's a shame CV&D doesn't seem to understand this.  They seem to
expect that a movement which can win prop rep at the state level will
somehow convince Congress to fix the Voting Rights Act, but Congress
has shown its willingness to disregard the successes of the term
limits movement, and if Congress is ruled by one of two large parties
they could disregard the prop rep movement just as easily.  

CV&D also seems to be in denial about the importance of the
Presidency in the U.S. system, and how difficult it will be to 
pass a Constitutional amendment to change from a Presidency to a
parliamentary system (which appears to be the only solution they'll
consider).  Perhaps we should start a discussion here about whether
the parliamentary system is better or worse than popularly electing 
the executive using a good single-winner method.

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