Dual Criminality

The requirement that both states agree — at least broadly — on what counts as a crime.

Dual criminality requires that the conduct at the centre of a mutual legal assistance request be recognised as a criminal offence in both the requesting and the requested state — not the specific charge or legal label, but the conduct itself. A requested state must determine whether the behaviour, had it occurred domestically, would constitute a crime.

In practice, the gap widens with complexity. Financial crime frequently involves conduct that sits at the edges of how different legal systems define criminalisation — clearly criminal in one jurisdiction, differently classified or unlegislated in another. Each gap is a legally sufficient basis for refusal, and assets continue to move while the question is resolved. Where the predicate offence is not recognised as criminal in the requested state, the money laundering charge collapses at the first condition.

The principle exists to protect states from enforcing foreign criminal standards that conflict with their own legal frameworks. That is a legitimate function. In grand corruption cases, it is structurally indistinguishable from obstruction.

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Definition drawn from the Basel Institute on Governance (Introduction to MLA)