The police main function would now be to control crime and prevent possible offenders of committing any crime. The heavy want for a police by individuals led to the approval of the London Metropolitan Act in 1829.
During the time of the civil war and the depression, American once again sought for a different form of policing to cope with the rapid changes. Political power ruled the area of enforcement in much of the nation. The higher officials in law enforcement where elected instead of hired from within the agency. Police had a duty to the political leaders in the area they patrolled. Policing varied throughout communities due to the relationships they built with the citizens in the area. The call for a more centralized force did not spread easily in the larger cities. Instead of adopting the new style of policing, the larger agencies incorporated certain aspects of the London style to the American decentralized system. .
The one aspect that both the centralized and decentralized believed was effective was the preventive patrol idea of a police presence in the community. The problem of the decentralized systems was that police had little power to enforce the law. Once the London model was accepted in larger communities it began to spread faster throughout the Eastern coast of the nation. There was also a large increase in political corruption in the years that followed the depression. Officers of any hierarchical standing would allow corruption in order to benefit themselves and those who did not agree with this way of work was demoted to other areas. .
By the end of the 1800's, many believed that the need for a professional police was at an all-time high. Upper class Protestants, known as the Progressives called for a professional police force that would eliminate any political linkage to the police. They believe that because much of the police where elected officials that they were not good leaders, not disciplined and where not qualified for the positions.