> political systems with single-member districts and the plurality voting system, as in, for example, the United States, two main parties tend to emerge. In this case, votes for minor parties can potentially be regarded as splitting votes away from the most similar major party
If a third party grows it will either shrink again as voters realize they are splitting their vote against their biggest common opponent, or the third party replaces one of the two existing parties. Either way, you get two main parties.
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 UK isn't a two party system though. It has at least 5 parties in play right now (Lab, Con, Reform, LibDem, SNP). Reform is only small but is currently polling higher than any other parties, so their number of MPs would go up a lot if an election was held today.
FPTP isn't sufficient to get a two party system. The US has such a system because it combines FPTP with open primaries. In the UK the right is trying to rebuild a new party from scratch, because the Conservative party has no working mechanisms that would allow it to have its direction changed by its members. Whereas in the US open primaries give members a great deal of control, and that kills the incentive to create new parties. The current Republican administration is run by a group of former Democrats who came into the GOP from the outside - this isn't possible in the UK system.
Yes, which reveals how serious they really are about third parties as "spoilers". An alternative voting system could eliminate that as a possibility entirely.
> 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.
When the national elections are still two party local, and the two big parties have any interest in the local election, those two parties will win local as well because they have some much more mind share. Many people decide who to vote for in the national election and then vote the same party all down the ballot without knowing what any of the other players stand for, thus giving the major parties a big advantage when one of those down ballot races is a different system. If you are not the big party in those other systems you still have a harder time because people don't understand how the local system is different.
Again, I ask, where has this two-party to multiparty switch happened with single member elections?
Because I can't find an example in any country, yet it is appears to be taken as an article of faith that it will happen by proponents of ranked choice voting.
The evidence for switching from single member to multi-member elections is far more clear. Of course, you obviously can't have multi-member elections for President, the Senate because the Constitution staggered elections and courts have ruled against multi-member districts for the House in the past for violating the VRA.
I'm not aware of enough world politics to tell you if it has happened. I would not expect such a change to happen overnight, instead it would take 50-100 years for people to get used to the change and then change how they act. Thus a lack of any examples doesn't mean it won't happen. (it also doesn't mean it will - politics are always changing)
> 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.
