[EM] "Unmanipulable Majority" strategy criterion

[Raph Frank]

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.