<P> Two developments were involved . </P> <P> Although the Civil Rights Act of July 2, 1964 forbade all discrimination on the basis of race, in 1965 police brutality towards a Black man during a traffic stop resulted in a major riot by among Blacks in the Watts neighborhood of Los Angeles Watts riots #Aftermath, the government's response to which is considered by many to have been a failure . (1). Indeed, every summer from 1964 through 1970 was a "long hot summer", though 1967 is particularly called that since 159 riots occurred that year Long, hot summer of 1967 . Additionally, after the April 4, 1968 murder of Martin Luther King, a new wave of riots broke out in over 100 cities, with nights of violence against police and looting and burning of local white - owned businesses . The inner neighborhoods of many major cities, such as Detroit, Los Angeles, Newark and New York, were burned out . National Guard and Army troops were called out . At one point machine gun units were stationed on the steps of the Capitol building in Washington to prevent rioters from burning it down . </P> <P> Secondly there was a dramatic rise in violent street crime, including drug - related murders, as well as armed robberies, rapes and violent assaults . Inner city neighborhoods became far more violent and people tried to move out to safer ones . The number of violent crimes more than tripled from 288,000 in 1960 (including 9,110 murders) to 1,040,000 in 1975 (including 20,510 murders). Then the numbers levelled off . </P> <P> In response to sharply rising rates of crime in the 1960s, treatment of criminal offenders, both accused and convicted, became a highly divisive topic in the 1968 U.S. Presidential Election . Republican Vice Presidential candidate Spiro Agnew, then the governor of Maryland, often used the expression; Agnew and Nixon won and were reelected in 1972 . </P>

What does the expression policing by the letter of the law mean