> Maybe try going outside, you'll find it's actually completly continuous, there is no species change when crossing state lines

Culture is different even in nearby states. I grew up in Virginia, went to college in Georgia, and live in Maryland now. Right before the pandemic my parents moved nearby, after living in Virginia for 30 years. My dad pointed out the other day that Marylanders aren’t like Virginians, something he has realized immediately. Then it clicked for me: Maryland is part of the mid Atlantic (PA, NJ, DE) while Virginia is part of the south. Now I can’t unsee it: the accents, the odd mannerisms, etc.

I married an Oregonian. Oregon might as well be Canada. Weird libertarian Canada. My family is originally from Bangladesh, but at least half of the cultural friction between our families comes from Oregon versus Virginia.

> Culture is different even in nearby states.

Yes, but the US is arguably much more culturally homogenous than many other countries. Whatever differences you see between Virginia and Maryland, I think they are significantly smaller than the differences between Ontario and Quebec. New York and Alabama may seem far apart culturally, but how does that compare to the cultural differences between Uttar Pradesh and Kerala, or between Sokoto and Akwa Ibom?

US cultural homogeneity is overstated by comparison to countries or regions with different languages. But Australia and Canada and the US are all English speaking—do they not warrant being separate countries? What about Australia and New Zealand? Ireland and Britain and Scotland? And language aside—are Denmark and Sweden more different from each other than New York versus Alabama?

> But Australia and Canada and the US are all English speaking—do they not warrant being separate countries?

Canada is also French-speaking. There are some big differences in attitudes between the US and Australia on various topics - for example, Australians have a mostly settled cultural consensus in favour of gun control and liberal abortion laws, to give two examples, unlike the US where both are very heated political conflicts

> What about Australia and New Zealand?

New Zealand actually participated in the negotiations for forming Australia (as a federation of British colonies), but at the end decided to stay out-if history had turned out a bit differently, it might have been an Australian state not a separate country. In a lot of ways the differences between Australian and New Zealand culture are relatively trivial - different accents, different words for certain things. You get the same differences between Australian states, albeit to a more limited degree.

However, there is one big difference: over 17% of New Zealand’s population have Indigenous (Māori) ancestry, and Māori have a common language and a great deal of common culture-leading to a significant Māori influence on mainstream NZ culture. Australia’s Indigenous peoples are less than 4% of the population, and divided among numerous languages and nations, which means their impact on mainstream Australian culture has been significantly smaller.

> Britain and Scotland?

One way in which the US is very homogeneous is that state politics aren’t particularly distinctive from national politics. Every state is the same two parties facing off against each other, the main political difference between states is the relative power of the two. Whereas, each of the UK’s four constituent countries have different party systems - the SNP only exists in Scotland, Plaid Cymru only exists in Wales, the major parties in Northern Ireland are different from those in the rest of the UK. Spain, Canada, India and Italy are other examples of countries in which region-specific parties are big players in politics. The only real example in the US are territories such as Puerto Rico, and if Puerto Rico ever became a state, it would likely start converging with the American political monoculture.

Politics isn’t the same thing as culture, but political culture is part of culture, and greater political diversity is generally both a symptom of and simultaneously a promoter of greater cultural diversity.

> There are some big differences in attitudes between the US and Australia on various topics

That's my point--just because places speak the same language doesn't mean they're culturally the same. Australia's response to COVID lockdowns versus America's is highly illustrative as well.

> One way in which the US is very homogeneous is that state politics aren’t particularly distinctive from national politics. Every state is the same two parties facing off against each other, the main political difference between states is the relative power of the two

American politics isn't homogenous at all--that's just an artifact of political narratives being filtered through mass media in New York City. To use your abortion example (because I agree politics is an expression of culture): black people in Georgia are overwhelmingly Democrats, while white people are overwhelmingly Republicans. But there is no racial difference on the question of abortion: https://www.pewresearch.org/religion/religious-landscape-stu.... Stacey Abrams, who grew up in Mississippi and Georgia (Atlanta), was always a democrat, but grew up opposed to abortion: https://www.politico.com/newsletters/women-rule/2022/09/23/s.... If the Democratic Party wasn't run by New York and California liberals and donors, Georgia Democrats would moderate on the abortion issue (because as a practical matter you don't want to play up issues that split your own voting bloc).

By contrast, Republicans west of the rockies are quite liberal on abortion due to a strong libertarian streak. Western Republicans tipped the scales to the social liberal side on key cultural issues in the past few decades. Reagan legalized abortion in California. Nixon and Reagan were California Republicans who appointed a bunch of Supreme Court Justices like Harry Blackmun (who wrote Roe). O'Connor (who wrote Casey) is from Arizona and was appointed by Reagan. Kennedy (who wrote Obergefell) is from California and was appointed by Reagan. Gorsuch (who wrote Bostock) is from Colorado.

> That's my point--just because places speak the same language doesn't mean they're culturally the same

Yes that's true. But I compare different Australian states – yes there are cultural differences even there, but they are pretty minor. If I compare US states – I'd say somewhat bigger cultural differences than between Australian states, for a bunch of reasons.

But still, my impression is, the cultural differences between US states aren't really that big by global standards. In some other countries, you have state/province/regional nationalist movements. Hard nationalists want their state/province/region to be an independent country – such as the Scottish National Party or Parti Québécois. You also have soft nationalists, who don't ask for independence, but seek greater national autonomy while staying in the federation – such as Quebec's current ruling party, Coalition Avenir Québec; or the former ruling party of India's Punjab state, Shiromani Akali Dal. The US has a few state-based nationalist movements, but they've never been remotely mainstream, none of them have ever controlled a statehouse or a Governor's mansion. The existence of regional nationalism is a sign of greater interregional cultural difference, so countries which have it (such as Canada, India, Spain, the UK) generally have greater interregional cultural differences than those which lack it (such as Australia or the US).

> American politics isn't homogenous at all--that's just an artifact of political narratives being filtered through mass media in New York City. To use your abortion example (because I agree politics is an expression of culture):

Okay, but on the other hand that actually is an example of American politics being homogenous – because the whole country is arguing about the same things, of which abortion is a big one. Compare that to the UK – the Protocol is arguably the biggest political issue in Northern Ireland politics at the moment, in England it is a lot further down the list of people's concerns. A never-ending political debate in Quebec is about how to balance the promotion of the French language with the rights of the Anglophone minority – a topic that isn't very interesting to the average person in British Columbia.

Your example is just that in some parts of the US, the national abortion debate doesn't neatly line up with the two national parties. Meanwhile other countries have completely different debates in different parts of the country, and even completely different party systems in different parts of the country. All are examples of diversity, but your example is a little bit of diversity compared to other countries which have a lot lot more.

Also, your point about "mass media in New York City" is another example of homogeneity – US media is very centralised, national, tends to focus on national narratives more than regionally specific ones – that media homogeneity is both a symptom and a cause of cultural homogeneity. The BBC has its own division for Scotland – many people in Scotland (especially nationalists) complain that BBC Scotland is too London-focused and doesn't provide enough coverage of Scotland's own politics and culture – but even if those complaints are valid, no doubt it is doing a much better job of being regionally-focused than the US media does.

I’ll disagree with the poster you’re responding to and admit that indeed, the states are not so culturally and geographically different that they need to be independent: surely, a rural hamlet in France is as different from Paris as any two parts of the US are.

But there are good reasons other than those to hope the states evolve towards more autonomy. The US political system at the federal level is fundamentally broken, making it incapable of governing the country. Due to a combination of factors: first-past-the-post voting, skewed representation in the senate, media polarization, the filibuster, and others, it is unique among supposed democracies in allowing small minority factions to effectively veto any mildly controversial legislation.

Because meaningfully modifying the constitution is functionally impossible, these issues simply can’t be fixed. But luckily, that isn’t true at the state level! Most states still are functioning, if imperfect, democracies, as evidenced by the very thing we’re discussing in this thread: they’re capable of changing policy in response to changing needs and wishes of the population, in a way that the federal level simply isn’t.