The differing roles of the police in the United States, Nazi Germany, and the Soviet Union demonstrate that the nature of police is determined by the quality of the political institutions under which the police operate. Thus, the police system is the effect of the political system and not the cause, and the police must be aware of the role of politics in their work. In addition, the main role of the police in modern Western democracies has been to maintain order and control crime. History also shows that the criminal laws are not effective in solving social problems like drug abuse and that the actions and policies of one time period may result in serious problems in later time periods. Finally, policing in Europe will change as the Single European Act of 1992 takes effect, and European police officials may find it useful to learn from the ideas and experiences of the North American police. 16 references.