I was reading over this question and was wondering why Maine and the other municipalities that adopted ranked voting use instant runoff voting. After reading the phrase ranked voting I assumed that people voting would rank the candidates from most favorite to least favorite and votes would be awarded based on position. For example if there was 5 candidates Voter A's most favorite would get 5 votes while Voter A's least favorite would get 1 vote. Many of the issues with IRV that were stated in the above question would be solved with this type of system. For example one of those issues was favoring radicals over moderates but with this system that would not be an issue. Has a system like this ever been used? Why is Instant Runoff Voting the accepted version of ranked voting?
The Borda count is inferior to Instant Runoff Voting (IRV) on several criteria:
- Majority. If a majority of all voters prefer A to B, then A should win.
- Mutual majority.
- Clone proof. If you add similar candidates, can choosing them cause your preferred candidate to lose.
- Later no harm. Voting for another candidate after your preferred candidate can't cause your preferred candidate to lose.
Instant runoff/alternative voting/preference voting/single winner transferable voting is old ( STV dates back to the 1850, IRV to 1871), fairly cheap to count and feels similar enough to plurality voting/first past the post that it doesn't require as much voter reeducation, or purchase of new voting equipment. A selling point often brought up is that "clones" don't generally split the vote to allow a less supported unique candidate to win. Note that the other main ranked voting system in use in international politics (the single transferable vote) collapses into IRV when you only have one winner.
The alternative you suggest sounds a lot like a type of range voting, which gets a fair amount of support from voting systems advocates, but seemingly not much from politicians.