I’m not very well-versed on all this but it seems
Edit: I don’t think this is the best, its just all I’m generally familiar with
First Past The Post
Benefits the two parties in a two-party duopoly system like that of the US. Boom or bust, black or white. When the party in power pisses you off you vote their competitor even if holding your nose.
Seems like there must be a better way, maybe just not as good for those who prefer shooting fish in a barrel
I like Condorcet methods.
This is a ranked method that’s different from instant runoff, with its defining characteristic being that the winner would beat every other candidate in a two-way race. The biggest downside is that determining the result is more mathematically complex than other methods, which makes it harder to explain and might lead people to mistrust the result.
Condorcet methods benefit candidates few voters hate, which is the inverse of the current and past two US presidential elections. Given a situation where two dominant parties run widely unpopular candidates, a Condorcet method would create a very strong probability that any palatable third-party candidate wins, though over the long term a system using such a method probably wouldn’t have two dominant parties.