The U.S. only has two parties with meaningful amounts of support -- Republican and Democrat -- and it has been this way (with few notable exceptions) since the 1800s. I've been told this seems very weird coming from countries with multi-party governments.

Ostensibly, the Democrats are the "party of the working people," but a lot of modern leftists (myself included) would argue that the vast majority are barely more worker-friendly than the Republican party.

It's also funny because many working people would say the exact opposite (though I would agree that the Democratic platform, nominally, includes the policies that are in their actual interest).

America's parties have done an astonishingly good job of divvying up the country along lines that really have much more to do with personal identity than with actionable policy, and getting us focused on working against each other instead of together. There are Republican workers and Democrat workers. Both think the other party is where the out-of-touch "elites" lie. Both are mostly right.

It's important to note that while there are only two parties, the parties clearly have sub-factions.

Trump for example is not what the GOP Republicans would be. He was his own thing and Trumpism fits within the Republicans, but has pushed out the GOP to the sides of the Republican party. Things like the Trade War would probably never have fit in with regular GOP Republicans. The brand of nationalism that Trump uses is very different from the traditional Republican nationalist rhetoric, which was generally okay with illegal immigration as long as it served the economic engine.

You have similar efforts in the Democrats - although no one has been successful like Trump has been. There is the traditional institutional Democrat (e.g. Pelosi, Obama, Clinton, now Biden) who operates with Wallstreet backing and largely benefits the neo-liberal agenda. You have the Sanders supports, who are not really Democrats at all, but Sanders implanted himself with the Democrats so now they're competing for control. Then you have the "Progressive" Democrats who are very pro-reform, identitarians, pro-socialism, bordering on very strong statism, possibly of the totalitarian variety. These are the AOCs, the Ilhan Omars, the "Squad".

All of the factions in the Democrats are trying to do what Trump achieved with the Republicans, but none have been able to dethrone the institutional Democrats so far. A lot of that is because they lack the impetus, but also because the DNC is extremely corrupt and openly aligned with the institutional Democrats.

So in short, while there are "only two parties", these parties are highly maleable and only really retain their names. If you go even further in history there are times where the parties essentially "flipped" in their entire positions on everything. Republicans, who are accused of being racist by the media were the anti-slavery party, while Democrats were pro-slavery.

This is partly due to a unique quirk of the US where someone who isn't a member of a party can run for its leadership, which is insane isn't it when you say it out loud like that.

Why do they allow outsiders to run to lead their parties?

In the UK you need to be a career member of the party to run as leader.

Because there are only 2 parties. It would be undemocratic to restrict who is allowed to run in them. More practically, the parties are not homogeneous, and there will always be factions that align more closely to groups outside the party.

The most relevent legel precedent I am aware of is Smith v. Allwright (1923), which ruled it was unconstitutional for a political party (the Democrats) to restrict primary voting to whites.

>When, as here, primaries become a part of the machinery for choosing officials, state and federal, the same tests to determine the character of discrimination or abridgment should be applied to the primary as are applied to the general election

> We think that this statutory system for the selection of party nominees for inclusion on the general election ballot makes the party which is required to follow these legislative directions an agency of the state in so far as it determines the participants in a primary election. The party takes its character as a state agency from the duties imposed upon it by state statutes; the duties do not become matters of private law because they are performed by a political party.

Granted, in this case, the court was looking at racial discrimination by the parties, which introduces direct constitutional concerns, and so has a lower bar to warrent governmental interference. However, the principle that "private" political parties are not actually private is fairly engrained in US politics (although the exact legal boundaries are still unclear).

https://supreme.justia.com/cases/federal/us/321/649/#tab-opi...

The UK and the USA are both based on the UK establishment's greatest invention: first past the post. This forces two parties.

One party is "pro establishment". Then you only have one party who is supposedly "anti-establishment".

At this point you only have one party head to keep an eye on.

If the mood turns ugly (and it won't often because the establishment own all the press/media), you have to fix the head of the one "anti" party now and again.

UK: use the media to circulate a smear campaign against Corbyn after he nearly got in power and surprised them

USA: use the media to ignore/denigrate/belittle Sanders as some kind of insane communist.

Trudeau campaigned on removing FPTP and as soon as he got in someone, somewhere told him to drop it like a hot potato. Legalizing weed was fine, even though this was apparently hotly contested before, because it's not a real issue and is there to be sacrificed when real power issues come up.

FPTP clearly does not force two parties, given as there are three substantial parties in the UK parliament, and seven more minor parties with seats!

Lib dems are always an insignificant bit-part.

They got 7.4% of the votes at the last election and 1.9% of the seats. Smaller parties like the green party do even worse.

By design.

> Lib dems are always an insignificant bit-part ... Smaller parties like the green party do even worse.

Smaller parties... like the SNP? 7% of the seats from 4% of the vote. Seems to fly in the face of what everyone says about what is possible under FPTP. And what's more they've been effective in influencing what happens in parliament!

Most of the time it converges on two parties.

Here's the "law": https://en.wikipedia.org/wiki/Duverger%27s_law

So you might think it's possible. But it's a case of in theory, in theory and in practice are the same, in practice, they ain't.

And that is what FPTP is designed for. To over-reward those at the top of the leaderboard. It's designed to not be representative.

>And what's more they've been effective in influencing what happens in parliament!

It's actually not that different in practice There are a large range on views in both parties, but you put on the Democratic or Republican label in order to build a majority coalition. This is sort of like how the Westminster parliamentary system works: labor forms a government with the greens. Labor has more seats by far is and is mostly in charge, but the greens get some government positions and a little influence on the agenda of state.

As a recent example of this here Bernie Sanders was not at all a Democratic party member but "joined" with them to try and get enough support.