Abstract: Since the democratization of the Nigerian polity on 29th May 1999, the major concern has been about meeting the challenges of consolidating the hard-won democracy. In this Herculean task, the police, under an ideal setting, stand out as one of the institutional structures capable of making meaningful contributions to the process. Its role is defined in terms of national security imperatives such as the protection of life and property as well as fundamental human rights of citizens, crime control, maintenance of law and order and other related responsibilities of effective policing. This study evaluates the performance of the Nigeria Police in these regards, pointing out its contributions and constraints. The study concludes that rather than serve as a viable instrument for the deepening of democratic values in Nigeria, the police have tragically served to undermine it. The task of effective policing for sustainable democracy, the study contends, calls for a comprehensive review of the police as an institution and a general reorientation and socialization among its rank and file.