Can a country refuse to extradite its own citizens?

Whether a person can be sent abroad to face trial often depends on their passport. Many countries refuse to hand over their own citizens to a foreign court, while others treat nationality as irrelevant. The answer to the question in the headline is therefore yes, in many places, but the position varies widely and is changing.

The nationality exception explained

The nationality exception is the principle that a state may decline to surrender its own citizens to another country. It is one of the oldest rules in extradition law. Where it applies, it is usually set out in a country's constitution or in its extradition legislation, not left to the discretion of individual officials.

Several reasons are given for it. States often feel a duty to protect their citizens from foreign legal systems. There is also a practical point: a person tried abroad may face a different language, different procedure and a distant prison. For that reason, the rule has long been a standard feature of the legal tradition of continental Europe and of countries influenced by it.

Civil law and common law approaches

The divide is often described as one between civil law and common law systems. Civil law countries have traditionally refused to extradite own citizens. Common law countries, including the United Kingdom, the United States and Canada, generally do not treat nationality as a reason to refuse.

Part of the explanation lies in jurisdiction. Common law systems have historically prosecuted offences mainly where they were committed, so a national who offended abroad could not easily be tried at home. Surrender was the only route to justice. Civil law systems more readily claim jurisdiction over their citizens wherever the offence took place, so refusing surrender does not leave the allegation unanswered.

Examples around the world

• Brazil: its constitution bars the extradition of Brazilians by birth. Naturalised citizens may be surrendered only in limited circumstances, such as offences committed before naturalisation.
• France: French law prevents the extradition of French nationals to many countries, though European Union arrangements operate differently.
• Germany: the Basic Law forbids extradition of Germans, with an exception for other European Union states and international courts, provided rule-of-law standards are met.
• China: its Extradition Law says a foreign request must be rejected where the person sought is a Chinese national.
• Japan: its law allows the government to refuse to surrender Japanese nationals.
• The United States and United Kingdom: nationality is not a bar. American legislation allows the surrender of US citizens even where a treaty does not oblige it.

Some countries have moved away from an absolute rule. Colombia, for instance, amended its constitution in 1997 to allow the extradition of nationals.

What the treaty says

An extradition treaty is the usual basis for a request, and its wording matters. Treaties between two civil law states often contain a clear ban on surrendering nationals. Treaties between a civil law and a common law state more often use an optional formula, allowing the requested state to refuse if its own law requires it.

Some treaties go further. They may require the refusing state to put the case to its own prosecutors instead, or limit a person's ability to change nationality once a request has been made. Others set aside the exception for particular offences. Nothing in general international law obliges a state to extradite in the absence of a treaty, so the text of the agreement and domestic law together decide the outcome.

Extradite or prosecute

Refusing to surrender a citizen does not usually mean the matter ends. Many treaties and international conventions rest on the principle known by its Latin name, aut dedere aut judicare: extradite or prosecute. A state that will not hand over a national is expected to submit the case to its own authorities.

That leads to cross-border prosecution in a different form. The home state tries the suspect under its own law, often relying on evidence, witness statements and records gathered abroad and shared through mutual legal assistance. This can be slow, and it depends on cooperation between the two countries. The offence must also be punishable under the home state's law, and outcomes may differ from those the requesting state would have sought.

Dual nationals and changes of citizenship

Dual nationality complicates matters. A person may be protected by one country's constitutional ban while also being a citizen of a country with no such rule. Which state holds the person, and whose nationality counts, can be decisive. Some laws look at nationality at the time of the alleged offence, others at the time of the request. Acquiring a second nationality after the event does not necessarily provide protection, and treaties sometimes address the point directly.

Europe's shift away from the rule

Within the European Union, the position has changed substantially. The European Arrest Warrant framework, in force since 2004, does not treat nationality as a ground for refusing surrender, and commentators regard it as a major factor in the decline of the nationality exception. States may still attach conditions, such as that a person be returned to serve any sentence in their home country.

Outside that system, the picture is less uniform. Some civil law states have also dropped the exception in treaties with non-European countries, but many continue to rely on it.

What this means in practice

A country can refuse to extradite its own citizens if its constitution, legislation or treaty obligations allow it, and many do. Others surrender nationals routinely, subject to the same court checks as anyone else. Even where the exception applies, it generally shifts the case to a different forum rather than ending it. Anyone trying to understand a particular dispute should look at three things: the law of the country holding the person, the wording of the treaty, and the person's nationality, or nationalities, at the relevant time.