The police should use physical force to the extent necessary to ensure compliance with the law or to restore order only when the exercise of persuasion, advice and warning proves insufficient to achieve the police's objective. goals; and police should use only the minimum level of physical force necessary on any particular occasion to achieve a policing objective” (Champion, 2001). Contrary to Peel's sixth principle, the broken windows theory was thought to be zero tolerance due to the harshness of the idea that out-of-control teenagers and anyone who disrupted social life would be punished, i.e. many minor crimes. “Patrol officers could be encouraged to go to and from service stations on public transport and, while on the bus or subway, to enforce rules on smoking, alcohol consumption, disorderly behavior and the like. The need for execution implies nothing more than the expulsion of the offender” (Kelling, 1997). However, in Fixing Broken Windows by Kellin and Cole they explain that it is up to the police officer's discretion to fix the problem (Kelling, 1997). That's why foot patrol was such an important aspect of Broken Windows