A preventive State is a type of sovereign state

Sovereign state

A sovereign state, or simply, state, is a state with a defined territory on which it exercises internal and external sovereignty, a permanent population, a government, and the capacity to enter into relations with other sovereign states. It is also normally understood to be a state which is neither...

 or policy enacted by a state in which people deemed potentially dangerous are apprehended before being able to commit a crime

Crime

Crime is the breach of rules or laws for which some governing authority can ultimately prescribe a conviction...

. As opposed to a punitive method, under which criminals are punished for their actions, a preventive policy seeks to stop people from being able to carry out crime. Several countries have deployed preventive measures as a means of Anti-terrorism in the wake of terrorist attacks; preventive measures can include intelligence gathering, detention and interrogation. Such extreme measures have raised serious concerns about liberty

Liberty

Liberty is a moral and political principle, or Right, that identifies the condition in which human beings are able to govern themselves, to behave according to their own free will, and take responsibility for their actions...

 and freedom in modern societies.