Say Bob commits some first-time offense while living in country B, and is a citizen of both country A (let's pretend is the United States to help paint a more clear picture on jurisdictions) and B (let's say is some European country), which is a federal crime in both countries. Let's say it was also some crime that involved some foreign exchange between the two countries, such as importing a bomb from Country A to be received to his house in B. If found guilty..

  1. Could he and would he be charged in both countries?
  2. Where would he be tried being that he is a dual citizen?
  3. If his conviction is able to spent sooner in country B, could he move to country B freely? Does he have to be forced to live in either country until he's served his sentence in both countries? Could he ever be unable to return to either country A or B and forced to live in the other even after serving his sentence?

4 Answers 4


Your citizenship only indirectly impacts where you are tried

Let’s keep things simple and make the crime murder.

If Bob commits murder in France, then France will try him if they have him in custody - it doesn’t matter if Bob is French, American, South African, or Japanese.

The same is true if Bob is in the United States, he will be tried there, usually under state law.

Now, if Bob has fled jurisdiction and is in custody somewhere else, then the state that wants to try him has to ask the state that has him to send him back. This is called extradition. Extradition is complicated. Some countries, including France, never extradite their own citizens. Others, including the United States, do, subject to treaties, law, extradition hearings and political considerations.

Some countries, like France, claim jurisdiction over their citizens no matter where they are in the world. This is called extra-territorial jurisdiction. It means that if French Bob murders someone in the USA, that is a crime in both the USA and France and, in theory, he can be tried and punished in both.

Others, like the USA, have very little extra-territorial law so if US Bob murders someone in France that is a crime under French law but not US law.

  • So Bob wouldn’t be tried by the USA if he imported the bomb from USA to France? Maybe it’s more complicated in that case - but the USA wouldn’t try an American citizen for a crime committed abroad even if it’s illegal in the USA? That sounds odd.
    – user38109
    May 24, 2021 at 15:54
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    The U.S. has a number of extraterritorial crimes, but they are generally linked to the U.S. based upon the victim or intended victim (mostly for terrorism and cyber crimes), rather than on the citizenship of the offender. Several countries have "universal jurisdiction" consisting of a right to punish anyone from crimes against humanity or war crimes committed anywhere.
    – ohwilleke
    May 24, 2021 at 17:40
  • sangstar, you'd need to check if "exporting a bomb" is a crime in the USA. Or "exporting a bomb to kill people". Or since you have to build a bomb before you export, they might charge him with "building a bomb to kill people". Or they could say that this was a terrorist attack and they might prosecute Americans commiting acts of terrorism anywhere in the world.
    – gnasher729
    May 25, 2021 at 12:49
  • Many countries don't prosecute anyone, including their own citizens, for most crimes committed abroad. If it is a plain murder case, not as complicated as you describe, the USA prosecutes murders in the USA, Germany prosecutes murders in Germany, and each country will extradite a likely murderer to the other country when asked.
    – gnasher729
    May 25, 2021 at 12:51

This depends on where Bob is arrested, and on the extradition agreements between the two states. Citizenship is a secondary issue, except for cases where countries do not extradite their own citizens (even dual ones).

Say Bob is arrested in A.

  • He could be charged in A and B, but only A has physical custody at this point. B must make an extradition request.
  • The legal system in A considers the request. It may decide to go ahead with their own case regardless of what B wants. Or it may defer their own case and extradite. Bob could usually challenge the extradition in court if he wants to stay in A.
  • If A does not extradite at this point, convicts Bob and makes him serve the sentence, then B can still keep their case and extradition request open. It might technically be a different crime (in your example building bombs vs. receiving bombs). The EU has double jeopardy protections which get complicated in this case.

If A still refuses to extradite after Bob has served the sentence, then Bob should make sure that he never goes to B (or a third country that would extradite him).

  • What if Bob was arrested in B (where A is the US and B is a European country)?
    – user38109
    May 23, 2021 at 16:52
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    Same principle. A might want to hold a trial, but B has custody. So A must make an extradition request.
    – o.m.
    May 23, 2021 at 17:02
  • Say in the worst case scenario Bob serves a sentence in both countries. Would anything ever bar Bob from travelling to either A or B again, given that he is a citizen of both after he is sentenced?
    – user38109
    May 23, 2021 at 17:34
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    @sangstar the ability to enter ones "own country" is commonly called the "right of return", and is enshrined in several international treaties - UN Universal Declaration of Human Rights 1948, UN International Covenant on Civil and Political Rights 1966, Fourth Geneva Convention 1950, UN International Convention on the Elimination of All Forms of Racial Discrimination 1969. en.wikipedia.org/wiki/Right_of_return This, however, does NOT mean you can enter ones own country without threat of repercussions for doing so (ie arrest, further charges etc).
    – user28517
    May 23, 2021 at 22:14
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    @sangstar anyone saying "I can't go back to my country" is typically leaving out "because if I do, something will happen that I don't want to happen," not "because the immigration officers won't let me in."
    – phoog
    May 23, 2021 at 23:34

In this particular situation, country A could claim that exporting a bomb is a serious crime, and country B could say that importing a bomb is a serious but different crime. Worst case: If he’s arrested in B, B will convict him and he spends time in jail. A will ask for extradition and B will tell them they have to wait. When B is released he goes to A and is convicted again. Possible because he committed two different crimes.

(If A=usa and he's lucky they will call it “double jeopardy”. Probably depends on how much they want to convict him.

  • The US is far from alone in prohibiting double jeopardy, but it is perhaps unique in that it doesn't extend double jeopardy across multiple sovereigns, so you can in fact be tried for the same crime in both state and federal courts. By extension, a foreign prosecution would also be treated separately.
    – phoog
    May 25, 2021 at 16:21

Hungarian Bob (in substance abuse hypo)

If the Member State of the European Union where Bob is from happens to be Hungary, Hungary seems to have very specific laws on extra-territorial jurisdiction.

It generally would not allow for what gnasher729 referred to as "double jeopardy", but certain duties would be imposed on Hungarian Bob as a matter of his citizenship.

For e.g. if Hungarian Bob snorts coke in the U.S. in public, he will go to jail there — provided he is reported and successfully prosecuted in the U.S.. Since he was already convicted there, when returning to Hungary, he will not be prosecuted by the government when home, and will unlikely to be bothered upon return after jail time. However, if Hungarian Bob used to roll up a spliff in Amsterdam until it was decriminalized generally without regard to citizenship, if Hungary finds out while Bob is back, Hungary will likely claim jurisdiction and prosecute Bob. It’s because the Netherlands will not prosecute it, and Hungary expects prosecution — either by the territory claiming jurisdiction practically on its behalf or it will seek to do it itself if learning about the violation.

In this sense, it respects other countries jurisdictions as long as they impose at least substantially the same level of duties on their citizens while abroad.

It's like having a conservative father that expects you to behave as uptight as you would in his presence — wherever you are.

  • 1
    "Hungary will likely claim jurisdiction and prosecute Bob": how likely is it really, for smoking cannabis? It's one thing for Hungary to reserve the right to prosecute, but it's another actually to do so. Given the difficulty amassing evidence (among other difficulties), it seems rather unlikely unless the crime is particularly serious, in which case it's also likely that the foreign authorities will prosecute in the first place.
    – phoog
    May 25, 2021 at 16:18
  • This scenario is very much in the realm of possibilities, Hungary is obsessed with marijuana prosecution. People may be locked up from 5 to 15 years for less than 3 pounds of weed. It’s only a matter of whether they get to take a blood sample or yet worse a cranial biopsy (I believe) and if substance is found, they will prosecute you, and you will not be able to raise a valid defense based on no jurisdiction on the grounds of having used the substance in the Netherlands or elsewhere. Also it used to be quite the touristy thing to do to go to Amsterdam and roll it up until decriminalized there.
    – kisspuska
    May 25, 2021 at 21:18

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