Why extradition looks at conduct, not just charges
An extradition request asks one country to surrender someone to another for prosecution or punishment. Dual criminality is a safeguard against using that process to enforce a rule the requested country does not recognize as criminal. The question is generally whether the underlying conduct would be a crime in both places—not whether both legal systems use the same name for the offense.
That distinction matters because criminal codes are organized differently. One country might charge conduct under a specifically named offense, while another could treat the same acts as fraud, theft, or a different crime. A difference in labels alone does not necessarily defeat a request; a meaningful difference in what the person is alleged to have done may.
How officials apply the test
The requesting country typically describes the alleged acts and identifies the offenses it seeks to prosecute. Authorities or a court in the country receiving the request then compare that account with its own criminal law. They are not simply asked to decide whether the foreign charge exists at home under an identical title.
The test can be difficult when laws define crimes differently—for example, when one system requires proof of a particular intention and another does not. The precise standard depends on the countries’ treaty and domestic law, so dual criminality is not a single worldwide checklist.
A safeguard, not an automatic guarantee
Meeting the dual-criminality test does not by itself require surrender. Other treaty or legal conditions may still matter, and the requested country applies its own extradition procedures. But the test draws an important boundary: a person generally cannot be extradited for conduct that the requested country does not treat as criminal, even when the requesting country gives that conduct a serious-sounding legal name.
