Societies differ both in their perception of public order and in the methods of its enforcement that they consider appropriate, and, of course, both may change over time in any given society. Modern societies have become accustomed to specialized law enforcement agencies called police that are authorized to regulate social conflicts, if need be, by employing physical force. They represent the state's claim to the ‘monopoly of legitimate physical violence’ (Weber 1972: 29, 183, 516) with respect to internal relations, whereas the army does the same with respect to the outside world. The establishment of a police apparatus that is supposed to guarantee impartial enforcement of the rules of public order and become functionally differentiated from the military forces is, however, a rather recent achievement from the perspective of universal history. The breakthrough to this solution during the eighteenth and nineteenth centuries arose out of new demands on public order but met with considerable objections as to the political dangers and the repercussions upon societal self-regulation that it would imply.

One of the leading proponents of police reform in late-eighteenth-century England, Patrick Colquhoun, called ‘police in this country … a new science; the properties of which consist not in the Judicial Powers which lead to punishment, and which belong to Magistrates alone, but in the prevention and detection of crimes, and in those functions which relate to internal regulations for the well ordering and comfort of Civil Society’.