In another thread I came across a post indicating the role of the police in the United States switched from peace keeping to "law enforcement" during the Nixon administration. The poster stated that this change affected the relationship between police and civilians as now the main job of police was to find law breakers/criminals versus protection/peace keeping. Is this assertion accurate?
It seems that much of this can be answered by http://www.theatlantic.com/health/archive/2012/03/the-war-on-drugs-how-president-nixon-tied-addiction-to-crime/254319/
"Nixon's was one of the last administrations to spend more on prevention and treatment than law enforcement and nearly every administration since (with the exception of Jimmy Carter's) worked to increase the division between prevention and enforcement spending."
Nixon also stated "our opinion-makers have gone too far in promoting the doctrine that when the law is broken, society, not the criminal is to blame." , which seems to mesh with this change of focus.
However, the shift in spending from preventative measures to law enforcement does not seem to require a shift in focus of law enforcement, merely a change in which organisation is getting the money.
The other interesting question, which I have not seen any direct answer to, is when police started referring to private citizens as "civilians", thus separating themselves from the population in contravention of Peel's Principles of Policing (and legal definitions). The shift in common use of the word (strictly defined as "not military") may well have started at about the same time.