I don't normally "this" a comment, but "this"!
The most effective single thing to promote a multiparty system is to switch to ranked-choice or approval voting (if staying with single-member districts) or to switch to multi-member districts with some kind of proportional representation. That would be where, say, everyone in Texas votes for their preferred party, and the 34 seats get allocated proportionally to party results.
Honestly, implementing Ranked Choice is the best compromise.
* Meaningfully improves the ability of minor parties to succeed
* Removes the concept of "wasted vote" so that citizens can vote their conscience
* Electoral results are more informative of the positions of the electorate
* Candidates have to compete more on ideas and policies than attacking opponents
* Conceptually easier to understand than other systems
* Maintains single-member districts (I don't like this, but I think trying to change the House to multi-member districts is too radical for us)
> The most effective single thing to promote a multiparty system is to switch to ranked-choice or approval voting (if staying with single-member districts) or to switch to multi-member districts with some kind of proportional representation.
The single best is to switch to multimember proportional for the legislature (which can remain candidate centric using, say, 5 member districts and STV), and that gets even better (though procedurally more difficult to adopt in the US) if you were to switch the Presidential election from a single winner two-seat President and Vice President to ranked choice two-sequential winner system (e.g., IRV or Bucklin, but after you pick a winner, eliminate that candidate, and tally again without them for a second winner as VP) where each party is structurally incentivized to compete for both spots. These not only make more parties viable they also each offer more election-day choice among candidates of the same party, denying incumbents of favored parties an uncontested sinecure.
Where has the adoption of ranked choice with single member districts resulted in a switch from a two-party system to a multiparty one?
It hasn't happened anywhere in the US as far as I know, despite being adopted by various local governments.
Ranked choice's major benefit is that it reduces the effect of spoilers. Third parties are the spoilers.
> implementing Ranked Choice is the best compromise.
Approval voting is the better compromise IMO. It has most of the same benefits, except that it's even easier to understand, and attacking opponents is even less valuable. You don't get as much information about opinions from the result, but you do still get more than the current system (assuming statistics are made available). You don't have to worry about people wasting their vote because they don't understand the new system, voting for only one candidate is a valid approval voting vote, it simply implies a higher threshold.
Ranked Choice (ballots) meaning Ranked Pairs (decision process), of course. Instant Runoff Voting is still thoroughly an artifact of the two party system.
The big issue, fatal even, is that the parties that can enact this change, those currently in power, are those that stand to lose the most from it.
So we're stuck with this joke we call democratic elections. Also seen in the UK with its abysmal first-past-the-post system.