Isn't the point of ranked choice voting to protect the duopoly from "spoilers"? If Ralph Nader's votes had gone to his voters second choice, Al Gore would have won Florida (using exit polls to determine his second choices). Once a party is freed from the spoiler rap, it can attract adherents who don't have to worry that they will be spoilers or "waste" their votes. That encourages a third party to take a stand and try to get more voters. The problem with the Green Party is not ranked choice voting; it's the Green Party.