Dual Criminality in Extradition Cases
Dual criminality usually asks a practical question, not a vocabulary question: would the conduct for which surrender is sought also amount to a sufficiently serious criminal offence under the law of the requested state? The answer depends on the governing treaty, statute and surrender regime. Many modern systems use a conduct-based test, so the foreign and domestic offences need not have the same name or identical elements. But that flexibility has limits: the alleged facts still have to supply what the requested state requires for a domestic offence, and territorial or penalty thresholds may matter. Some regimes also remove or relax double-criminality review for defined offences. A defence therefore starts with the exact request, the applicable legal instrument and a charge-by-charge map of the alleged conduct—not with a search for matching offence labels. [2] [3] [5] [7]
What the test actually compares
There is no single universal formulation. Article 2 of the European Convention on Extradition uses a punishment-threshold formulation: the offence must be punishable under the laws of both the requesting and requested Parties, subject to the Convention’s thresholds. The UN Model Treaty takes a more explicit conduct-oriented approach: differences in offence category, terminology or constituent elements do not necessarily defeat extradition when the totality of the acts or omissions satisfies the required criminality. Canada states the point directly in section 3(2) of its Extradition Act: it is not relevant whether the conduct is named, defined or characterized in the same way by the extradition partner and Canada. These formulations show why “the statutes are different” is not, by itself, a dual-criminality defence. [1] [2] [3]
The opposite proposition is equally important. A conduct test is not a licence to invent facts or to replace the conduct described in the request with a broader narrative. The competent decision-maker in the requested state asks whether the legally relevant conduct alleged by the requesting state would constitute a domestic offence under the hypothetical required by its own law. If an indispensable domestic ingredient cannot be supported by the alleged facts, dual criminality may fail even though the foreign charge sounds similar. [2] [3] [4] [5]
Conduct test, elements and legal characterization
Canada provides a clear example. In Canada (Justice) v. Fischbacher, the Supreme Court of Canada explained that the foreign and Canadian offences do not have to match in name or constituent elements; the domestic side of double criminality is satisfied when the conduct underlying the foreign offence would amount to a Canadian offence carrying the required penalty. The court described Canada’s approach as conduct-based. [3] [4]
The United Kingdom also applies a conduct test under the Extradition Act 2003, but the statutory hypothetical can make geography decisive. In El-Khouri v Government of the United States of America [2025] UKSC 3, the UK Supreme Court held that the relevant alleged conduct occurred outside the requesting state, so the statutory test required corresponding conduct to amount to an extraterritorial UK offence. It did not. The appeal was allowed and the extradition order was quashed. The case is a useful warning: “this conduct would be criminal if done here” may be the wrong question when the statute requires a corresponding-circumstances or extraterritorial analysis. [5] [6]
A charge-by-charge decision matrix
| Issue | What to test | Why it can change the result |
|---|---|---|
| Governing instrument | Identify the treaty, convention and domestic extradition statute that actually govern the request. | The instrument fixes the threshold and may modify or disapply ordinary dual-criminality review. [1] [5] [7] [8] |
| Conduct alleged | Extract the acts, omissions, mental-state allegations and legally relevant context from the request. | A conduct-based system tests the alleged conduct, not merely the foreign offence title. [2] [3] |
| Domestic analogue | Ask which offence in the requested state the alleged conduct could constitute. | Names and elements may differ, but the facts still must support the domestic offence used for comparison. [3] [4] |
| Territorial nexus | Test where the relevant conduct occurred and whether domestic law criminalizes equivalent extraterritorial conduct. | El-Khouri shows that territorial rules can defeat dual criminality even where similar conduct is criminal domestically in other circumstances. [5] [6] |
| Penalty threshold | Check the minimum treaty/statutory seriousness threshold in both states. | Criminality alone may be insufficient if the applicable maximum sentence or remaining sentence does not meet the governing threshold. [1] [3] |
| Exception or waiver | Check whether the regime removes verification for listed offences or permits surrender despite lack of dual criminality. | Some instruments deliberately relax the rule; ordinary analysis cannot simply be carried over. [7] [8] |
How six regimes frame the dual-criminality question
| Regime | Rule relevant to dual criminality | Practical consequence |
|---|---|---|
| European Convention on Extradition | Article 2(1) requires punishability under both laws and the Convention’s seriousness threshold. | Article 2(2) also gives the requested Party the right to grant extradition for other offences in the same request that are punishable in both states but fall below the punishment threshold. [1] |
| UN Model Treaty on Extradition | Different offence categories, terminology or constituent elements do not by themselves defeat the test; the totality of acts or omissions is considered. | Article 2(4) also permits lower-threshold offences to accompany at least one extraditable offence. The Model Treaty is a model framework, not a self-executing universal rule. [2] |
| Canada | Section 3 makes conduct determinative; identical naming, definition or characterization is unnecessary. | The conduct must constitute a Canadian offence meeting the applicable statutory or agreement threshold. [3] [4] |
| United Kingdom, Part 2 | Section 137 uses different conduct tests depending on whether the relevant conduct occurred in or outside the requesting territory. | For outside-territory conduct, corresponding-circumstances analysis can require an extraterritorial UK offence, as El-Khouri demonstrates. [5] [6] |
| European Arrest Warrant | Article 2(2) removes double-criminality verification for 32 listed categories when the issuing-state maximum is at least three years. | This is a distinct EU surrender rule and must not be imported into ordinary extradition. [7] |
| UNCAC Article 44(2) | If its domestic law permits, a requested State Party may extradite for a Convention offence not punishable under its own law. | This is a permissive treaty exception, not a general abolition of dual criminality. [8] |
Where dual criminality is relaxed or displaced
Dual criminality is common, but it is not absolute. Under the European Arrest Warrant regime, Article 2(2) of Framework Decision 2002/584/JHA removes verification of double criminality for 32 listed offence categories when the issuing-state maximum penalty is at least three years. That is a distinct EU surrender regime, not a rule for ordinary extradition. The United Nations Convention against Corruption also illustrates treaty flexibility: Article 44(2) permits a State Party whose law allows it to extradite for Convention offences that are not punishable under its own domestic law. The correct question is therefore not “is dual criminality always required?” but “what does the governing instrument require for this request and this count?” [7] [8]
Evidence that matters in a dual-criminality challenge
The most useful working file is an allegation-to-offence map. For each count, isolate the conduct actually attributed to the requested person; identify the domestic offence said to correspond; list each domestic ingredient that must be supported; record the territorial rule and penalty threshold; and cite the part of the request that supplies the necessary fact. This exposes two different problems that are often confused: a true legal mismatch, where the alleged conduct cannot constitute the domestic offence, and an evidential-description problem, where the request does not state enough facts to apply the domestic test. [2] [3] [5] [6]
Litigation strategy: six questions before arguing “no equivalent offence”
- What instrument governs this surrender, and does it require dual criminality for this count?
- What precise conduct—not offence label—is specified in the extradition request?
- Which domestic offence is the requested state using as the analogue, and what facts are indispensable to it?
- Does the statutory hypothetical require transposition of place, actors or other circumstances, and does extraterritorial jurisdiction exist?
- Are the applicable punishment thresholds satisfied in both systems?
- Is there a listed-offence, treaty or statutory exception that removes or relaxes verification?
A strong challenge should identify the exact failure in that chain. Saying that the foreign offence has a different name, broader drafting or different elements is usually too abstract. Conversely, the requesting state cannot necessarily rescue a deficient request by pointing to any domestic crime that could be imagined from background facts. The permissible factual basis and the degree of transposition are questions of the requested state’s extradition law. [2] [3] [4] [5] [6] [7] [8]
Practical conclusion
Dual criminality is best treated as a structured comparison of conduct, domestic criminalization, territorial reach, seriousness thresholds and any regime-specific exceptions. Modern extradition law often tolerates differences in labels and elements, but it does not erase the requested state’s own limits on criminal liability. For a live case, the decisive documents are normally the extradition request and charge materials, the governing treaty or convention, the requested state’s extradition statute, and the domestic criminal provisions relied on as analogues. The analysis should be repeated count by count because one charge may satisfy the test while another does not. [1] [2] [3] [5] [6] [7] [8]
Sources and legal materials
- European Convention on Extradition, ETS No. 24, Article 2
- UN Model Treaty on Extradition
- Canada Extradition Act, section 3
- Canada (Justice) v. Fischbacher, 2009 SCC 46
- UK Extradition Act 2003
- El-Khouri v Government of the United States of America [2025] UKSC 3
- Framework Decision 2002/584/JHA, Article 2(2)
- United Nations Convention against Corruption, Article 44