[EM] serious strategy problem in Condorcet but not in IRV?

[James Green-Armytage]

Dear election methods fans,

In the sort of strategy scenarios that I have been talking about, one
fairly positive possibility occurred to me. Take my ABC examples for
instance. (Let's assume that the method being used is beatpath Condorcet,
using defeat magnitudes rather than margins.)

Example 1: Sincere preferences. 
46: A>B
44: B>A
5: C>A
5: C>B

Example 2: Sincere preferences.
30: A>B
25: B>A
23: C>A
22: C>B

	What I am hoping is that maybe candidates and parties in the position
that A and B are in will be moved to broker some sort of truce agreement
whereby neither party instructs their supporters to use a burying /
offensive order reversal strategy against the other party. 
	Or even a truce where the parties actively encourage their supporters to
rank the other fellow second rather than truncating, assuming that this is
their sincere preference.
	Such a truce would make good sense if neither candidate knew exactly
which one of them would win out of the two of them, which is a pretty
common situation in real elections.
	A truce would be especially in the interest of both candidates in example
#2, where they may know that neither of them can beat C without each
other's second choice votes.

	(Also, from a political perspective, candidates who engineered such a
truce would be better situated after the election even if they didn't win
than a candidate who had gone all out in a serious smear campaign /
burying strategy drive and then still lost.)

	Let me see if the use of strategy tables will clarify 
	Here is the strategy table for example #2 as I expressed the scenario in
previous postings, where all candidates have a precise notion of voters'
sincere preferences, especially concerning the result of the pairwise
competition between A and B.

		A buries	A truncates	A sincere
B buries	C wins	C wins	B wins		
B truncates	C wins	C wins	A wins
B sincere	A wins	A wins	A wins

	Here is a strategy table where the result of this pairwise competition is
uncertain. "AB equal" means that there is a roughly equal probability that
A or B will win the comparison.

		A buries	A truncates	A sincere
B buries	C wins	C wins	B wins
B truncates	C wins	C wins	AB equal
B sincere	A wins	AB equal	AB equal

	It looks to me like A and B have more incentive to cooperate with each
other in the second table. (If this is the case, then banning polls two
weeks before the election might not be a bad idea...) Is there anyone here
who is good with game theory? 

my best,
James



P.S. Please let me know if I have made any calculation errors.
P.P.S. I wonder why none of the IRV advocates on the list aren't arguing
that the Condorcet strategy flaws are serious. I think that this is the
point on which Condorcet is most vulnerable, and it would help Condorcet
advocates sharp if they came up against the strongest available arguments
on the subject. I am basically a Condorcet advocate myself, so it is not
especially easy for me to be the one pressing for a harsh look at
strategic incentives under Condorcet...