IRV example where voting for somebody makes him lose, while voting against him makes him win

#voters Their Vote
5 A>C>B
6 C>A>B
4 B>A>C
2 C>B>A

In this 17-voter election, A is both the IRV (Instant Runoff Voting) and the Condorcet winner. (Pairwise victories: A beats B 11-6; A beats C 9-8.)

If the C>B>A voters in the bottom row decide to "betray their favorite" C by voting B>C>A instead, then IRV elects that very favorite C! (A is eliminated then C wins 11-to-6 over B.) That, from the point of view of these voters, was a huge improvement, i.e. the favorite-betrayal worked to get the best winner for them instead of the worst. And this shows how actually honestly voting for your favorite, in IRV, can hurt both you and that favorite maximally, whereas voting against him can make him win, helping you and him maximally. Indeed even voting maximally against him (i.e. if the C>B>A voters had voted B>A>C) here makes him win. (Just voting for him doesn't work!)

This IRV phenomenon is truly an example of the mirror world. Voters in this situation would feel they've been transported into a backwards universe.

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