> The interpretation of US law by a GB judge seems extraneous. For the extradition treaty to apply, it must be alleged that the defendant has committed actions

> The interpretation of US law by a GB judge seems extraneous. For the extradition treaty to apply, it must be alleged that the defendant has committed actions which amount to a criminal offence in both countries. If his alleged actions are not a criminal offence in both countries, then the extradition treaty does not apply. Therefore, you can challenge extradition on dual criminality by arguing that the act is not a crime in one or both countries.