Basic Information
Anarcho-Tyranny is the - apparently tautological - state of dystopian society where the state is both authoritarian and incompetent. Typically in this state of affairs the generally law abiding and compliant are harshly policed, with severe penalties for relatively trivial offences, whereas the non-compliant are not policed at all, or are penalised ineffectively for crimes committed. It is also entirely normal for one or more privileged castes to be able to "float above" the enforcement regime.
This is a trope beloved of cyberpunk, but could equally apply to early modern settings where policing is partial and/or embryonic. The type of dystopia will often depend on why law enforcement is incompetent in some areas - the trope requires that laws exist but are not competently enforced.
The grey and black-markets thrive in this sort of environment, as regulatory regimes make legitimate business hard - and again, this will favour either huge corporations with the administrative, financial and legal muscle to weather the storm, or traders small enough to fly under it.
Another theme may be that crimes against the state are more closely policed than crimes against the person - indeed the state might even pride itself on its "progressive" approach to crime and strongly resist any "vigilante action" or other actions of self defence or retaliation by the victims. This is, effectively, bringing the evil of school "zero tolerance" policies into the adult world. In practice, punishing all involved in a fight will be disproportionately hard on the generally compliant, as the generally non-compliant are either hardened to penalties or have little to lose.
Sources
Game and Story Use
- By way of an example, this might be the sort of regime where you can receive an eye-wateringly expensive ticket for a minor traffic violation from a cop who appears to be deliberately ignoring a nearby drug dealer.
- Another example might be a society whose punitive regime relies entirely on fines - if you belong to a indigent class, fines are irrelevant as you have no money for the state to take, and if you are rich enough the fines are trivial, but for the "squeezed middle" a constant stream of fines is a significant drain on your livelihood.
- The RPG friendly aspect often lies in regimes in which the sheer number and complexity of laws precludes their effective enforcement - thus creating a need for (plausibly) deniable assets who can operate outside the law to achieve necessary outcomes.
- Technically this trope can be layered on top of several other forms of government - it's more of a failure state than anyone's idea of how things ought to be done.

