Nevada recently approved a ballot measure to implement ranked-choice elections, joining Maine and Alaska. As its advocates campaign in other states, should Alaska leap off the ranked-choice bandwagon? Critics contend that it is confusing. That complaint is partly overblown: most Americans have little difficulty ranking pop songs, movies or ice cream flavors. Why not rank candidates for office? The system can be quickly described. Voters rank as many candidates as they like, votes are counted using first-place rankings, and if no candidate wins 50% or more, the last-place candidate is eliminated and any second-place rankings from those ballots are then used along with the first choices from other ballots in a second round. The process repeats until some candidate wins a majority of the ballots counted in that round. Tabulation need not be extremely slow.
There is, however, a disturbing feature of ranked choice that is easy to miss. It is, in technical jargon, non-monotonic: gaining more support can convert a winning candidate into a loser.
Consider a stylized example, featuring candidates A, B, and C, where “ABC” signifies ranking A first, B second, and C third, and so on. Seventeen voters have the following rank orders: 4 ABC; 2 ACB; 6 BCA; 3 CAB; 2 CBA. The initial count, using only first-place rankings, yields A 6, B 6, and C 5. With no candidate breaking 50% of the vote, last-place C is eliminated, and the 5 ballots on which he was ranked first are transferred to the second-ranked candidates in the next tabulation, 3 going to A (the CAB ballots) and 2 to B (the CBA ballots). The second round then results in an A victory over B, 9-8 (53%-47%).
But suppose, instead, that an impressive speech by A, attacking B, convinced 2 of the BCA voters to re-order their rankings to ACB. No one else changes, so the revised counts are: 4 ABC; 4 ACB; 4 BCA, 3 CAB, 2 CBA. The winner, A, has strictly increased her support, which should not hurt.
The first count is now A 8, B 4, C 5. No one wins the seat, and B is eliminated. The 4 BCA ballots go to C by second-place ranking, and the second count yields C 9, A 8. Candidate C wins. Candidate A loses precisely because she persuaded some voters to rank her more highly. From the tabulations alone, observers would not know that A’s loss originated in her own persuasive campaigning, so the curse of gaining new support can be invisible.
Are reversals of this kind likely to be common? It is difficult to say without making many assumptions. Maine’s short experience with ranked-choice has mostly seen general-election races with one Democrat and one Republican splitting most of the vote, while some additional candidates draw enough support that some extra counts and some small vote transfers are required to determine a winner. But Alaska, and now Nevada, combine ranked choice with a so-called “jungle” primary election in which all candidates appear on one ballot and the top few, whatever their party, advance to the general election. The scope for perverse results is greater with more candidates and more evenly spread support.
Ranking allows voters to convey more information about their preferences than picking only one candidate. But not all the information collected on the ballots is used. As the example shows, which second-place choices are counted and which are ignored can matter. Supporters of small parties favor ranked-choice because they believe that plurality rule shrinks their vote, as potential backers switch to their favorite of the major-party candidates, to avoid wasting a vote on a likely loser. Such strategic voting is less tempting with ranked choice. Is there an electoral rule that uses all the information on the ballots and forestalls strategic voting? Alas, no.
There is no perfect electoral system, but if you find it troubling that candidates can be harmed by getting higher rankings, then discarding ranked-choice and returning to most-votes-wins elections in Alaska should appeal.
• Brian J. Gaines is the W. Russell Arrington Professor in State Politics at the University of Illinois. Columns, My Turns and Letters to the Editor represent the view of the author, not the view of the Juneau Empire. Have something to say? Here’s how to submit a My Turn or letter.
