And of course, since NYC is a Democratic city, the Democratic primary effectively is the election. Ryan Heath tells us "How NYC messed up its mayoral election," Politico Nightly, 6.22.21. Thus:
When Nightly contacted each of the top candidates, not one of them had a plan for telling their voters how to rank the rest of the candidates on their ballots. [...]
That’s Election 101 stuff in Australia, my home country and the global capital of ranked choice voting, where the system is used in all elections from college campuses to federal elections.
When running under a ranked choice system, you make deals:
In a ranked choice system, self-interest dictates that a candidate should make deals with rivals and communicate those deals with voters. But admitting you need voters who think you’re only second-best is the antithesis of New York toughness.
The lowest-ranked candidates could have formed a coalition to take on the big shots, while the more left-wing candidates such as Maya Wiley, Scott Stringer and Dianne Morales could have worked together to blunt the moderates at the top of opinion polls.
Instead it was moderate Kathryn Garcia who did most to explore preference deals, and even that was half-hearted. She failed to return the favor when Yang recommended her as his second choice.
Australia’s experience with ranked choice voting shows that deals among candidates can affect the results. Australian candidates have won ranked choice elections with as little as 0.2 percent of first choice votes. Senator Ricky Muir won a Senate seat in 2013 after starting with 0.5 percent of the vote: He vacuumed up another half million or so votes from voters who ranked him second or lower, closing a 400,000 vote gap. (Muir is an exception, though. The main outcome the system has led to in the Australian Senate, where eight parties are represented, is diversity without gridlock.)
More common are “Anyone But X” campaigns. In San Francisco, mayoral candidates Jane Kim and Mark Leno formed a tactical alliance against Mayor London Breed, getting within 2,500 votes of unseating her in 2018.
I wonder if anyone has used game theory to analyze campaign tactics in ranked choice voting systems? This would be a multiplayer game situation, which I understand can be technically challenging.