Community policing has existed since at least the nineteenth century, when law enforcement began building positive relationships with communities in order to establish mutual trust between the two groups. Modern community policing started in the 1980s with what is known as the "broken windows" theory. This approach has been controversial, but essentially it means that police should focus on minor crimes in a community. Since these small signs of social disorder in an urban environment have the potential to lead to more serious ones, this tactic is focused on prevention. This approach was adopted by many cities in the United States, most famously by New York City in the early 1990s. Like other aspects of community policing, it focuses on preventing crimes rather than responding to them.
Also, in the 1980s through the 1990s many community policing efforts focused on assigning particular police officers to conduct regular foot patrols in specific neighborhoods. The idea was that these police officers would be a visible part of the community to which they were assigned. This would build trust between the civilians and the law enforcement.
In 1994, the Clinton administration established the Office of Community Oriented Policing Services (COPS). This office of the Justice Department conducts research, establishes guidelines, and provides funding for community policing initiatives across the country. As a result, community policing became a standard throughout the United States during the 1990s.
The biggest evolution in community policing today has to do with the role of social media. Taking the same approach as a police officer walking a beat, but applying it to the social media landscape, police departments regularly engage with their communities online. They can quickly and directly communicate with the community with these platforms, and community members can directly respond. Many police departments have reported that the use of social media in community policing has done a lot to foster relationships between the police force and their community.