Although the historical roots of the jury system and common law tradition in the United States are shared by the states, punishment mechanisms vary according to political culture, party politics, and state demographics. Debate among states and localities in regard to the appropriate policing method has centered on the use of the professional model versus the community model. While punishment mechanisms and policing initially were designed as deterrents (professional model), policing has evolved into a social mechanism. The community policing model, or broken windows policing, has been adopted by most states as a way of discouraging minor disturbances and preventing community-wide problems.
Contemporary policing faces numerous dilemmas, including sustaining cooperation among law enforcement agencies, recidivism, fluctuating crime rates, and the disproportionate presence of certain groups in the criminal justice system. There is general agreement, however, that the community policing model is the most reliable mechanism for ensuring a fair and quality criminal justice system.