I think you have alot of redundant language, is the criterion effectively the following?
If the winner is preferred to another candidate on the majority of the ballots, it must not be possible to make any such candidate win by modifying the ballots where that candidate is preferred to the winner. By requiring that at least 3 levels are possible, you are effectively forcing lots of methods to fail. Also, just because most methods would meet the criterion in the 2 candidate case isn't a reason to exclude that case. ---- Election-Methods mailing list - see http://electorama.com/em for list info
