[EM] 04/03/02 - Adam needs a method that will win elections for his party:

[Adam Tarr]

Don Davidson wrote:

>Adam, you are confused.  It is not a weakness of IRV that it does not
>interfer with the voters and with an election when it does not break the
>system out of a two-party duopoly.  Instead, it is the strength of IRV that
>it allows the public to break the system out of a two-party duopoly,
>provided that is what the public wants to do.

OK, imagine the polls before election night show the following first-place 
preferences:

Favorite 30%
Compromise 26%
Worst 44%

Almost every Favorite voter likes Compromise more than Worst, and almost 
every Worst voter likes Compromise more than Favorite.  The supporters of 
Compromise are split 50-50 between Favorite and Worst.  This is, I hope you 
realize, a quite realistic scenario.

Now say that I'm a supporter of Favorite.  What would you, Donald Davidson, 
advise me and those like me to do?  If we vote Favorite in first place, 
Worst will beat Favorite 57-43 or somesuch in the runoff.

But if me (and others like me) bury our favorite and vote for the "lesser 
of two evils" in Compromise, we can get Compromise to win the election 
56-44 over Worst.

This is how IRV keeps the two-party duopoly going.  Even after a third 
party (favorite, in this example) is more popular than the party nearest 
it, the voters will still abandon that party for the more moderate 
party.  So the new party will seem weaker than it really is.  IRV keeps 
third parties down.

>Mike wrote:
>But 3 different Australians have told me that it's common for
>preferrers of 3rd parties to insincerely rank one of the big-2 in
>1st place, so as not to "waste [their] vote".
>
>Donald: I don't believe this.

I think the scenario I bring up explains how and why this happens.  I 
suppose you will say some rhetorical nonsense like "we can't compare the 
two sets of ballots", but clearly those voters in Australia can.

-Adam