P.A.J. Waddington 
Policing Citizens [PDF ebook] 
Police, Power and the State

This analysis of policing throughout the modern world demonstrates how many of the contentious issues surrounding the police in recent years — from paramilitarism to community policing — have their origins in the fundamentals of the police role. The author argues that this results from a fundamental tension within this role. In liberal democratic societies, police are custodians of the state»s monopoly of legitimate force, yet they also wield authority over citizens who have their own set of rights.