Mistake of Law

When a perpetrator of an international crime argues in his defence that he did not realise that he had violated the law, is this a reason not to punish him? International crimes constitute serious offences and it could be argued that he who commits such an offence must know his act is punishable. After all, everyone is presumed to know the law. However, convicting someone who is mistaken about the wrongfulness of his act may be in violation of the principle ‘no punishment without guilt’. This bo