It would seem that the definition of state crime is straightforward: any state-sanctioned conduct by individuals or organizations representing the state that’s in violation of the ethical standards by which the state operates might be categorized as state crime. What’s tricky about the idea of state crime is that the state is traditionally the author and executor of the criminal law. Ruling parties have of course been accused of criminal acts by the people they rule for as long as cities have existed. But in order for these accusations to be treated as “crime” – that is, deviant behavior that must be punished and corrected – then the state itself has to acknowledge that it’s committed a crime and, well, punish itself. :) . If the state doesn’t acknowledge that its actions are criminal then the people have no option other than to grumble acquiescently or plot revolution. The problem is, it’s very difficult to punish itself unless it acknowledges a higher authority. I suppose that’s why we’re lucky to live in a “nation of laws” rather than kings… more or less.
An even sticker situation with state crime is when an international tribunal – a collection of representatives of several or many different nations – decides that another country’s government is guilty of crimes against its own people. What if that nation doesn’t recognize the authority of the tribunal? It’s difficult to enforce criminal justice on a country that doesn’t acknowledge the authority of the enforcer. Of course, the tribunal could always simply invade the “criminal offender”… I mean, “employ military intervention.” Justice has always been one of the finest reasons to start a war.