Other countries with first-past-the-post have many parties. So FPTP does not cause two-parties - that's clearly nonsense.
Maybe tone doesn't come across well in written communication, but dismissing this as "clearly nonsense" without bothering to engage with the merit of the claim or, seemingly, even read the link seems disrespectful, to say the least.
Do you want to rephrase? :)
> In political science, Duverger's law holds that plurality-rule elections (such as first past the post) structured within single-member districts tend to favor a two-party system.... In the course of further research, other political scientists began calling the effect a "law" or principle.
(Emphasis, of course, added.)
The article goes on to note counterexamples, to drive home the point that this is not, as you say, like a law of physics.
Perhaps a more constructive phrasing you could have tried would be something like,
"As noted in the linked article, there are many counterexamples, so while as you say first-past-the-post may encourage two-party systems, it doesn't preclude more parties from existing."
This would have been a more polite phrasing, one that shows you read and comprehended both my comment and the article I linked to, and one that would not exhibit the logical fallacies your original comment does (to argue that the existence of counterexamples precludes any causal relationship between first-past-the-post and two-party systems).
Hope that helps. Have a nice rest of the weekend.
In the UK:
A small but national party was in government a few elections ago. They had multiple ministers and could influence the policy narrative.
In the previous government, the DUP, a tiny regional party had a big influence on major policies that mattered to them.
The SNP, a regional party, has wiped away the national parties and now has many seats in the national parliament, and was recently part of frustrating the main party from doing anything.
This is all possible, even with FPTP.
Imagine if a party like the Greens, or the SNP, or the LD, but in the US, controlled a few seats in the Senate or the House of Representatives - think how much power they'd become king-making between the two parties. They'd be able to insist on a couple of their key policies for the deal and be able to enact real changes.
"There are also cases where the principle appears to have an effect, but weakly...In the United Kingdom, the SDP–Liberal Alliance, and later Liberal Democrats, between the February 1974 and 2015 elections obtained 1–10% of seats forming a third party, albeit with significantly fewer seats.[16] This share of seats is despite gathering around a fifth of votes consistently over the same time period.
In the UK there is no president and thus no unifying election to force party mergers and regional two-party systems are formed. This is because Duverger's law says that the number of viable parties is one plus the number of seats in a constituency."
Which ones do you have in mind? The one's I'm thinking of have two main parties, and then strictly regional parties which displace them entirely in their regions.
> So FPTP does not cause two-parties - that's clearly nonsense.
Many European countries with non-FPTP systems have coalition governments all the time and there really are several viable major parties.
To be fair, preferential voting isn't a panacea (and arguably should be paired with multiple-representative electorates). Here in Australia we have instant run-off voting and there are still two major parties with even less crossbenchers than the UK parliament -- though our Senate does have a fair few independent and third-party candidates, likely because Senate seats aren't winner-takes-all (like electorate seats are for the House of Representatives). I think voter education is also partially to blame -- many Australians seem to not be aware of how preferential voting works.
I disagree - it's about influencing the policy narrative. It doesn't matter if you have plurality or not if you are getting things done.
The LD, the SNP, and the DUP (a tiny tiny party) all managed that recently in the UK.
A small party with large support somewhere like California could become king-makers in the US, and influence police, nominations, etc.