Carrol, what is the difference between a cop who uses tear gas on crowd of protesters, and a unionized worker who produced that tear gas? Aren't they both in a same position - alienated from the product of their labor that is being used to defend the capitalist system that oppresses them?
Let's face it - police work is no more or less unethical than the work of people who manufacture weapons, surveillance equipment, automobiles that destroy aour social fabric and natural environment, computers that allow capital owners to maximize their profits etc. etc. Every society, even a socialist one, needs law enforcement - the problem is not the law enforcement per se, but its abuses.
These abuses fall into two broad categories. The first category comprises systematic efforts of policy makers to subvert the public mission of the law enforcement system to benefit special interests groups. The most often discussed case is the harassment of political enemies of the ruling class or unpopular minority groups - but ironically, this form of abuse is very rare in this country (the only vase I can think of is Manuel Noriega). A much more common form of this systematic abuse is selective non-enforcement, that is, a failure to enforce certain laws and prosecute their violators (cf. corporate and white collar crime).
The second category of abuses are latent malfunctions that result from the organizational structure of law enforcement and the type of social interaction involved in police work. Most cases of police brutality fall into this category - they result from the combination of organizational factors, such as poorly formulated or misguided policies and procedures of their implementation, inadequate supervision, or inadequate personnel selection (e.g. cops unfit to do police work professionally), and situational factors i.e. the nature of the police work that is highly complex, confrontational, and requiring non-routine decisions.
A blatant example of abuses in this category is LAPD corruption (cf. posting by Carl Remick) - misguided "war on crime" policies of Darryl Gates, lax supervision, and ulterior motives of some officers lead to a situation in which cops used their positions for their own personal benefit. Another example, more widely spread but less visible is the "satisficing" behavior of cops and prosecutors - going after less serious but easier to detect and prosecute offences (such as recreational drug use or minor traffic violations) while neglecting more serious but difficult to investigate and prosecute cases (white collar crime, environmental pollution, burglary, homicide).
Very few people, other than the most zealous law-and-order types, would deny the fact that US law enforcement sufferes from latent malfunctions due to its organizational structure and the nature of police work (yes, the US is a very violent society!). Moreover, no respectable politcal forces would condone this sort of malfunction, and as the mainstream media report, police departments are in fact investigated for this type of abuse. So the system does work to police itself - although we may wish that it worked more effectively.
I do not see any special benefits the Left may get from jumping on that bandwagon already full of the liberal forces. Adding a voice to that chorus without spending much energy on that cause might be OK, but it will not uniquely define the Left in public eyes. The strategy of distinction by notoriety, being more catholic than the pope, and zealous cop bashing (as some leftish cults do) will almost certainly lead to a loss of credibility.
On the other hand, systematic abuses of law enforcement in the form of turning a blind eye on white collar and corporate behavior can be a legitmate "law enforcement" issue for the Left. Since not too many mainstream political forces (especially liberals who are very soft on white collar crime) are willing to espouse that cause - that Left can gain public salience and credibility here. Moreover, this issue has a clear affinity to workinbg class interests, as most white collar/corporate abuses are directed against the intersts of the workers.
To summarize, stop cop bashing and whining about police brutality - the liberals are already doing it. Focus instead on what the law enforcement does NOT do, or does very poorly, control of the upper class behavior. In fact, my main complaint against the prison system in this country is not that it houses 2 million of lowlife - but that there is virtually no highlife among those 2 million.
wojtek