It is hard to lose your US citizenship either accidentally or on purpose. Oddly, one way to do the former is to enter the United States using your other passport. This somehow means you are entering the country under the protections of your other citizenship.
For some historical reason this seems to set off alarms and stuff.
I cannot say I completely understand it, but I do not suggest you try it.
IANAL. However, I think the issue is less about what happens once you’ve gotten past passport control and are safe at home, and more about what might happen AT passport control - if you’re coming from a country, using that passport, then you may need to show a visa or a return ticket. Without these, you may run into trouble.
My brother-in-law was a dual Canadian/US citizen (he has since the event I’m about to describe formally renounced the US part). They did notice him using his Canadian passport one time, and read him the riot act about how he shouldn’t do that, though the reasons weren’t tremendously clear.
Since he considers himself Canadian, the US part being an accident of birth, he renounced the US part to prevent future issues, since he travels a lot for work (as an employee of the Canadian Federal Government).
So, it’s not actually illegal, it seems, but the US border guards will definitely look at you funny, which can cause problems for many other reasons.
This. What will happen is that when you get to passport control, either you will have to show all the visa etc stuff that a non-citizen must provide or else you will have to haul out your US passport and they will get annoyed with you for wasting their time. Which is why I travel to the US on my US passport and back to the UK on my UK one. So much simpler.
In the hypothetical, however, overstaying a visa could at the very least get you into trouble, some of which could be mitigated by the revelation that you’re a US citizen but I guarantee you that the Immigration people would very definitely ask you “why” and do not have a sense of humor about this sort of thing.
A citizen wouldn’t. But then a citizen would normally be using a US passport to enter the US in the first place. In the hypothetical, the person is entering on the foreign passport - which would require a visa to do.
The person would certainly not be required to leave after ninety days; a citizen has, of course, a right to be in the country indefinitely, and that right does not hinge on the passport that was used to get in. What would probably happen is that after ninety days, it would be logged as an overstayed visa (or visa waiver admission) because there was no departure registered to match the entry. As I understand it, however, US authorities are not in the business of actively searching for tourists with overstayed visas, so I guess nothing would happen at first. The issue would pop up next time this person’s passport is scanned by immigration officers. This would look, to them, as a case of overstay at first but could then be clarified when the person’s citizen status is demonstrated. It would certainly annoy the ICE but not breach any laws.
Then again, I’m a lawyer but not an immigration lawyer, so I can’t vouch for the accuracy of these guesses.
I had read a while ago that it is mandatory to enter the USA with your American passport if you are a US citizen. The comment was mentioning a citizen of Israel who was born in the USA when his parents were working there (for the UN?) and left for Israel before he was a year old. He was flying into the USA for the first time to go to a business meeting on his Israeli passport and was denied entry, sent home. (He had never gotten a US passport)
What if the reason was that the US passport had expired and it proved impossible to renew during the pandemic? This occurred to me since my US passport expires in a couple years, while my Canadian one has more than five years remaining. The latter shows clearly that I was born in the US, so the border guard wouldn’t need any online search to realize that I was likely a US citizen.
So what happens under normal circumstances if a U.S. citizen wants to return, and their passport has expired (or is lost or destroyed)? They obviously have not lost their rights, they just don’t have the preferred document that would make entry straightforward.
I had dual Canadian U.S. citizenship. Lived all my life short a few days in Canada. At one time I only had a U.S. passport because oddly enough it was quicker to get in a hurry. Returning to Canada from overseas a pleasant discussion ensued with the border control person. He informed me that it could cause an issue due to entering on the U.S. passport, that it would at some point throw a flag that I had overstayed. I went on to get my Canadian passport. If that issue of overstaying ever did flag, it was never pursued, maybe the issue was correctly identified and resolved in the system, or just never happened. Possibly the border guard inserted a note that avoided it.
I realize the OP asked about the US but I’m going to digress.
It is more straight forward in countries that do not recognize dual citizenship (or multiple citizenships). Cases happen routinely in China. China does not recognize dual citizenship. So, when a person born in China goes to the US, becomes a naturalized US citizen and then returns to China on a Chinese passport because it is more convenient (no need to get a China visa). China considers said person with two passports to be Chinese, subject to Chinese law and not a US citizen. And there is pretty much zero that the US can do to support that dual national. I suspect, but don’t know, that most countries that only recognize single citizenship operate this way.
To get back to the OP and the US. When my kids were born in China, they were dual nationals. China has exit immigration controls (eg, you have your passport checked before getting on a plane), and requires a valid visa to the destination country. So, we would leave on a Chinese passport with a pro-forma US visa. Essentially, the US Embassy would issue a pro-forma or fake visa for my kids Chinese passport because being US citizens, my kids could not apply for a US visa. US citizens don’t need a visa to the US, therefore dual nationals are not allowed to apply for a US visa in their other country passport.
The US consulates in China were pretty accomodating in the early 2000’s with pro-forma visas, but turned into complete dickheads in 2004. I tried to keep the dual citizenship thing going, but with China not recognizing dual citizenship and the US actively discouraging dual citizenship (at least at that time), it was too difficult to keep the dual citizenship going. Basically, I had to agree to renounce their Chinese citizenships in return for the last “pro-forma” visa, went to the Chinese consulate from LAX and had their Chinese passports cancelled.
I am 99% sure that US immigration regulationsrequire dual citizens to enter the US with their US passports. And that all sorts of complications can happen when they don’t.
For the OP, I think immigration and criminal status is 99% clear when a dual citizen returns using a US passport. It gets into a grey area for immigration or if crimes are committed when entering the US with the foreign passport. For example, claiming protection from extradition to another country.
I suspect this is generally true of any county: if there are rights and responsibilities attached with being a citizen of that country there isn’t really anything the US can do about it. I doubt there’s a formal reason why the US can dictate what a country does with it’s own citizens within its borders even if they are US citizens too; although I’d admit that there might be additional “soft” diplomatic pressure they might be able to exert and get away with depending on the power dynamic between the US and that country.
I hadn’t actually thought about what the US requires when entering. I’m a dual citizen between the US and South Africa. I know South Africa has a requirement that you enter on your South African passport, so I’ve always used my US passport to enter the US and my South African passport to enter SA (and whatever passport is most convenient for visa requirements for 3rd party country travel, which is typically the US passport).