[tialaramex]

Inherited citizenship is very different, the US has fairly weak inherited citizenship, it relies way more on granting citizenship by reason of presence in the country at birth.

Suppose both your parents were born in country X to country X citizens from a long line. They live in country X all their lives, until one day at say, 35, they move to country Y.

They then settle in country Y, you are conceived soon after and born there, you grow up there, you think of Y as your home.

Do you have citizenship of country X? Of country Y? Neither? Both?

The US says if X is the USA then you are NOT a citizen of the US. Your parents (who are citizens) could bring you into the country, and do the paperwork, and you would probably qualify, but not automatically. The longer you all wait, the more unlikely it becomes. Once you're 18, you are just another foreigner if you didn't already start the process.

The US also says if Y is the USA, then you ARE a citizen of the US, regardless of almost anything else.

Some countries operate almost the reverse rule. For example if X is Ireland then you're an Irish Citizen, but if Y is Ireland you probably aren't unless X was the United Kingdom or your parents had some other form of "enduring connection" to Ireland.

The only overall principle is that all UN members have agreed not to create "stateless people". That is, if there appears to be no citizenship you're entitled to, somebody has to pick up the slack and make you their problem. The US system is simple in this respect - if there's an unexplained baby born in the US, Americans just give it US citizenship. Simple. The rules against statelessness are partly because statelessness is a colossal bureaucratic problem and the UN would much rather its members stopped making it worse, but also because has an enormous human rights impact, statelessness usually means you can't get decent treatment anywhere because everybody says you aren't their problem.

[nebulous1]

> The US says if X is the USA then you are NOT a citizen of the US

That is not correct. In the majority of cases the child will be a US citizen at birth, and the parents do not have to bring the child to the US.

> Once you're 18, you are just another foreigner if you didn't already start the process.

Also incorrect. Even if no application is made until the child becomes an adult, application can still be made for derivative US citizenship.

> if Y is Ireland you probably aren't

Again incorrect, assuming by "settled in Y" you mean gained permanent residency.

[tialaramex]

I evidently had this completely wrong, I can't now correct it, so I've upvoted those pointing out that it's wrong.

[jcranmer]

Uh, you're wrong.

The USA has both jus sanguinis (you're a citizen because your parents were) and jus soli (you're a citizen because you were born in the US). The jus soli provision is written into the Constitution to prevent Southern states from trying to deny citizenship to emancipated slaves via a grandfather-like clause; if you were born in South Carolina, you are a citizen from birth of both the US and South Carolina, and there's nothing South Carolina can do about that.

If you are born to US-citizen parents in, say, France, you are automatically a US citizen, and you can get a US passport even if you haven't been to the US for the first 30 years of your life. The rules become more complex the more tenuous the connection becomes, but the US does apply a jus sanguinis path to citizenship as well.

[tialaramex]

I evidently had this completely wrong, I can't now correct it, so I've upvoted those pointing out that it's wrong.

[kevin_b_er]

We'll have jus soli until corruption of the Executive and Legislative branches permits a full take over of the Judicial branch and it kills the 14th amendment through clever wordsmithing.

[dragonwriter]

> The US says if X is the USA then you are NOT a citizen of the US.

That's absolutely not true if your parents are married (children born in-wedlock to parents who are both US citizens, at least one of whom has ever been present in the US, acquire citizenship at birth by operation of law; there is paperwork to get a certificate acknowledging this, but it is an acknowledgement of something that happened by virtue of birth.)

A similar rule applies but with a more stringent prior residency requirement for the US Citizen parent for in-wedlock children of a US citizen and an alien that occur outside of the US.

Out-of-wedlock overseas births to at least one US parent have permissive (under certain circumstances) acquisition of citizenship rather than automatic, with different rules for US citizen fathers vs. US citizen mothers.

See, https://travel.state.gov/content/travel/en/legal/travel-lega...

[tialaramex]

I evidently had this completely wrong, I can't now correct it, so I've upvoted those pointing out that it's wrong.