Zero-tolerance policing (ZTP) is one (but not the only) policing embodiment of the principles of 'broken windows theory' (Kelling & Coles, 1996). The thesis is remarkably simple:
If a window in a building is broken, and is left unrepaired, all the rest of the windows will soon be broken ... [O]ne unrepaired broken window is a signal that no-one cares, and so breaking more windows costs nothing.
Put simply broken windows theory posits that the failure to tackle 'minor incivilities' and low level offending can lead to an escalation of offending behaviour, because the localities concerned enter a downward spiral of neglect leaving a space for more serious crimes to be committed.
A piece of property is abandoned, weeds grow up, a window is smashed. Adults stop scolding rowdy children; the children, emboldened, become more rowdy. Families move out, unattached adults move in. Teenagers gather in front of the corner store. The merchant asks them to move; they refuse. Fights occur. Litter accumulates. People start drinking in front of the grocery; in time, an inebriate slumps to the sidewalk and is allowed to sleep it off. Pedestrians are approached by panhandlers (beggars) ... Such an area is vulnerable to criminal invasion (Wilson & Kelling, 1982).
The corollary is that the 'assertive policing' of anti-social behaviour and low-level criminality can interrupt this cycle of neglect and 'win back the street' from wrongdoers. This is the essence of ZTP: the uncompromising policing of low level disorder is employed as a means of challenging the 'space' that such disorder gives to more serious offending. In some ways this approach would stand full square against community policing, in the sense that the latter would allow for a discretionary style of policing which might tolerate certain types of offending behaviour (such as possession of less serious drugs) if it is deemed counter-productive in some communities to enforce the law strictly. ZTP by definition would leave little or no space for such discretion because it considers such tolerance the thin end of the wedge of a 'broken windows' scenario.
Famously, in the 1990s in New York USA, under Mayor Rudi Giuliani (Bratton, 1997), law enforcement officers adopted ZTP strategy and tactics (although they were not named as such), first on the underground train system where they tackled graffiti, drunkenness and fare avoidance, and then on the streets, where they disrupted begging behaviour, 'squeegee merchants' and the like. Over time, or at least it was claimed, serious crimes such as robbery declined dramatically (Bratton, 1997). The ZTP model, as a consequence, attracted world-wide attention, particularly from politicians keen to exploit the evident populist appeal of ZTP (Jones & Newburn, 2007, pp. 110-111).
It is, however, crucially important to acknowledge that ZTP was not just about a certain style of 'street policing' - it was also, at least in its New York form, inseparable from a certain management style. Under Giuliani's chief of police, William Bratton, the New York Police Department was broken down into 76 'mini-police departments' (Bratton, 1997, p. 35), each headed by precinct commanders, who were given strict performance targets under the 'Compstat' (Comprehensive Computer Statistics) regime, which provided detailed management information on precinct-by-precinct performance. Commanders were placed under massive pressure to achieve targets under an intensive managerial 'accountability' programme (Bratton, 1997, p. 38). The extent to which any 'successes' of ZTP New York style is attributable to a street policing style or the pressures of Compstat is much debated in the field (see Dixon, 1998).
ZTP, in some form or other, was to spread to other countries (Punch, 2007), either under the direct influence of the New York experiment, or as a parallel development to it. In Britain it was more of a case of the latter, in the sense that when it did emerge - in a rather isolated fashion in Cleveland in the north-east - it appeared to have developed separately from but in parallel with its New York equivalent (Jones & Newburn, 2007, pp. 130-142). It was most closely associated with a middle ranking officer, Ray Mallon (who was later to become a local mayor) (see Dennis & Mallon, 1997). Mallon explained his 'style' of policing as follows:
Criminals, like house burglars, have a career path which starts with anti-social behaviour so we decided to concentrate our resources on tackling that. I told the officers to get intimate with this sort of behaviour and yobs. Where appropriate, they should arrest people, but just also confront them...It gets the message across that we're there and it brings some discipline to the streets which had been lost. (Police Review 13/9/1996).
Brixton riots through-out the 1980s and 1990s were said to be the result of growing tensions between black and ethnic communities and the Metropolitan Police.
Of course, bringing 'discipline to the streets' has its dangers, and one reason why ZTP did not really take off as a policing model in Britain was the concern amongst senior police chiefs that such 'aggressive' policing is precisely what went wrong in Brixton (see Orr, 1997). Ironically, although ZTP aims to reduce police discretion by 'tolerating nothing', it also can maximise police discretion by enabling police officers to decide which 'behaviours' and which 'offenders' are to be policed aggressively.
Broken windows theory need not, however, find its policing expression in ZTP. Another policing model also operates on the basis that early intervention is an important part of policing, but in a very different way: 'problem-oriented policing'.