Police are used for collecting fines for municipal budgets. This has been a long-standing practice in speed traps, where heavy fines are levied on drivers, usually on highways outside of town; since locals know where the speed traps are, it falls mostly on strangers (similar to resting your budget on hotel taxes in popular tourist destinations). Cities where there is strong resistance to tax increases, or which have serious budget short-falls, often explicitly adopt the policy of increasing fines for all sorts of infractions. It then becomes the police duty to seek out offenses, however trivial; they are expected to produce at high rates, sometimes with quotas set by police officials (Moskos 2008). This was a notorious practice in Ferguson, where the protests began after police shot a young man who defied an order about walking in the street.
In Philadelphia, Alice Goffman (2014) showed how computerization of court records and police communications has intensified pressure on persons (mostly minorities in the ghetto) who have some kind of previous record. Offenses may range from drugs to violence to gang association; police stops on the street immediately run a computer check in their car, above all for outstanding warrants. These often involve failure to appear for a court hearing, or failure to pay fines, since the penalties for everything include fines. It becomes a vicious cycle as fines mount up. The courts are overburdened, and this combined with attempts to reduce over-sentencing to prison, results in most offenders being released but required to make future appearances and pay fines which they can’t afford. Persons caught up in the system no longer can get a bank account, a legitimate job, or driver’s license — which generates further fines. Police, as the front-line enforcers of the system, are understandably unpopular. On their side, police also regard the criminal justice system as a revolving door.
 Police are used for enforcing unpopular regulations. A long history includes prohibition on alcohol (now mostly passé except for prohibitions on young people); prohibitions on marijuana (ditto). All of these promote counter-cultures of defiance. There have been many examples during the stay-at-home lockdowns during the coronavirus plague. Public parks have been closed, playing ball prohibited, beaches and/or their adjacent parking lots are closed; children’s playgrounds roped off. In many instances, ordinary people find these prohibitions inconsistent or irrational– areas closed even if people maintain their distance; young people who have heard the statistics and know that their chances of surviving the coronavirus are above 99 percent. It appears that another counter-culture of defiance is building up today, likely to become exacerbated during the phase of opening up public activities under a regime of masking and social distancing. To a considerable degree, this coincides with conflict between age groups.
What many people regard as trivial offenses can escalate when officials enforce the rules. In San Diego, a black man walking his dog in a state park (actually the old Spanish settlement) was accosted by park rangers; when he refused to leave, they called police backup, who arrested the man; when exiting the police car downtown, he slipped his handcuffs, ran away, and was shot and killed. His mother said he was schizophrenic and did not understand the order to wear a face mask. (San Diego Union-Tribune, May 6, 2020) This is the archetype of many such events: one damn thing leads to another.
[2a] Police hypocrisy and cynicism. In both  and  police are required to carry out the dirty work of government. When this becomes the primary part of their job, it makes them cynical and hardened. They know that it doesn’t necessarily make sense to punish harmless violations, or that they are lying when they say their city-mandated increase in traffic stops are purely in the interest of public safety. In their own work lives, they are under a regime that demands hypocrisy; after a while, this unpleasant feeling turns into a bitter that’s-the-way-it-is. Like prison guards who have to play the role of the bad guy, they embrace the tough-cop image. (Striking descriptions of this are in Jennifer Hunt’s 2010 close-up ethnography of the NYPD.) Citizens who argue with cops about these things increase the tension; one reaction is to be more aggressive. Taking videos of the police is felt as threatening them; and this can lead to attempts at retaliation.
 Police dislike defiance. Jonathan Rubinstein (1973), a sociologist who joined the Philadelphia police in order to study their everyday life (similar to Peter Moskos in the Baltimore PD 30 years later), found that their number-one priority is to be the person in control in all encounters with civilians. For the most part, a cop is out there alone, or with a single partner; they are almost always outnumbered by civilians. Particularly in areas where they know they are unpopular, they feel it is imperative to not let things get out of control. They want to be the one who starts and ends the encounter, who sets the speaking turns (micro-sociology of conversation), who sets the rhythm of the interaction. Acts of defiance, whether micro-actions on the level of voice and gesture, or more blatant words and body movements, will cause a cop to increase their own aggressiveness in order to maintain dominance (Alpert and Dunham 2004). This a reason why trivial encounters with the police can escalate to violence far beyond what seems called for by the original issue.
[3a] Inner-city black code of the street emphasizes defiance. Elijah Anderson’s ethnography of black street life (1999; also Krupnick and Winship 2015) point out that in dangerous areas, where the police are distrusted, most people adopt a stance of being hyper-vigilant about threats and disrespect, and portray themselves as ready to use violence. Anderson says this is mostly a Goffmanian frontstage, a pretence at being tough designed to avoid being victimized. When dealing with the police, this leads to another vicious circle. Black people, particularly on their home turf, are more defiant of police than are whites; often this is no more than a confrontational way of talking, but these are micro-interactions that arouse police aggressiveness. Anderson notes that one reason people in the ghetto are wary of calling police is that they themselves may end up being arrested, because of the tone of these micro-interactions. Donald Black (1980), who pioneered observer ride-alongs in police cars, found that police arrested black suspects more than whites, but this happened when black people were defiant, which was more often than whites. Martín Sánchez-Jankowski (1991) in his gang ethnographies (including black, hispanic, and white) describes the culture of gang members as “defiant individualism.” The pervasiveness of the street code in black lower-class areas, even among the majority who are not sympathetic with a gang life-style, hardens mutual hostility between citizens and police.
 Police dislike property destruction. Anne Nassauer  who studied protest demonstrations in the US and Germany by compiling videos of these events, was able to pin-point the conditions that led to a turning point where violence broke out. One of the major conditions was when police could see protestors destroying property, but were unable to do anything about it; this happened if they were under orders not to respond, or when they had relatively limited forces compared to the numbers of protestors. Normally police are concerned to prevent robbery and vandalism; it is one of their more favored duties, since they get to be the heroes protecting people. But now they are in a situation where they have to stand by and let it happen. This builds up their frustration. Although they may perceive that only a small part of the crowd is doing the destruction, they dislike the crowd for providing the opportunity to get away with it. Given further trigger events during the protest– more on this in – police will take out their tension and anger on whoever is nearby in the crowd.
Property destruction in a mass demonstration puts police in a damned-if-you-do, damned-if-you-don’t dilemma. If they take action against looters and arsonists, they get accused of whatever violence they use and casualties they cause. If they stand by and let the destruction happen, they are accused of neglecting their duty and not caring. Eye-witnesses to such scenes are particularly likely to be outraged (see letters to the editor in recent days).
 Adrenaline overload and forward-panic attacks on unresisting targets. When tension builds up, humans experience rising heart rate, driven by adrenaline. At a high level, perception narrows in, time becomes distorted, fine motor control is lost. Nassauer found that the level of tension is visible in videos: whether the police are in relaxed or tense postures, and similarly with the crowd. When tension builds up, from escalating gestures of confrontation, unexpected movements by crowd or police units, police getting surrounded and cut off, a trigger point sets both sides in action. Adrenaline is the fight-or-fight hormone; it produces generalized arousal of the large muscles of the body, but in what direction will it go? Police, like soldiers, are trained to respond to high adrenaline arousal by attacking. Most civilians, of the other hand, will run. But the one reaction feeds back on the other. The crowd suddenly running away is felt by the police as a release of their own tension into action.
In interviews (reported by Nassauer and others), police say they can see the crowd is divided between peaceful demonstrators and a small number of trouble-makers; but when the situation boils over, the crowd is infected by the violent ones. –This is how the police perceive it; what happens is that the panic of the crowd running away puts the police in an over-the-top rush of adrenaline in which their own perception is narrowed. When police rush forward, they become likely to strike those who have fallen down, or are screaming uncontrollably. The content of what people are saying is lost; all that is heard is the sounds and sights of out-of-control people. Since the police are trained to operate as a unit, officers who rush forward with their comrades tend to imitate what they do; if they are striking someone on the ground, it must be for good reason, and they will join in or protect them.
I have called this “forward panic” because it is like a panic flight where the overwhelming emotion of the crowd increases individuals’ adrenaline level; but in this case, the adrenaline is driving them forward, towards an easy target who have their backs turned, running away or falling down.
Police who have been in shoot-outs generally report that their senses are blurred, they have tunnel-vision, can’t hear the sounds of their own guns, don’t know how much time is passing (Artwohl and Christensen 1997). They also tend to fire wildly, with poor aim, and with an overkill of bullets as they empty their magazines. It is similar with those who deliver a large number of blows with their batons, or put their full weight on a captured suspect’s neck. It is the same in military massacres (with a higher level of casualties because of more weapons). There is the same time-sequence: a period during which tension has built up on both sides; a sudden tipping point when the tension is released; one side becomes incapable of resisting (because they are caught in a traffic jam, fallen in the mud, turning their back, running away); the result is hot rush, piling on, overkill.
In real-life situations, violence is usually incompetent– in the sense that it often fails to hit its intended target, or hits the wrong target, or is disproportional to what is necessacry to prevail. Soldiers and police are much more accurate shooters on firing ranges than they are in the emotional conditions of real-life confrontation.The clichés of military and police officials refer to “surgical strikes” and proportionate response. But the military is all too aware of “collateral damage”, especially in counter-insurgency warfare, where violent enemies hide in the civilian population. This is a close analogy to confronting peaceful protests in which aggressive militants cover themselves.
 Police training for extreme situations. Police training tends to emphasize the worst-case scenarios. Knowing that firing in real-life situations is encumbered by high adrenaline, weapons instructors tell them to aim middle-mass– the center of the body; don’t try to shoot for extremities like arms or legs (the cowboy movie myth of shooting a gun out of someone’s hand never happens). The result is, police shootings tend to be deadly. Emphasis also is on rapid reaction; in the worst-case scenario, the suspect is armed and dangerous; you have to train your muscle memory to react as quickly as possible.
There is sometimes training in how to calm dangerous situations, but this tends to be overshadowed by the quick reaction scenario: your life or someone else’s life is in danger; train yourself to react automatically.
Another process that enhances the atmosphere of worst-case scenarios is police communications. When police call for backup, they tend to emphasize the danger of the situation. When the call is propagated more widely, the message is propagated just as rumors are: the distinctive elements are dropped out as the message is repeated. A man on a highway overpass threatening suicide by jumping, will get transformed into the cliché– suicidal and threatening to take someone else with him — into armed and dangerous. This is how individuals end up getting shot dozens of times by an aroused network of converging cop cars. The distortion may start when a civilian calls in, starting with an ambiguous situation, which the police dispatcher (a civilian employee), transforms into the more conventional warning. This was the case with the famous incident in 2009 when a Harvard professor, a black man, arrived home and had difficulty getting his front door open, getting the taxi driver to help un-jam it. A well-meaning Harvard secretary passing on the street phoned to say a possible burglary might taking place, but did not mention anyone’s race on the 911 recording and said: “I don’t know if they live here and they just had a hard time with their keys”. The dispatcher transformed this into a house-breaking by two black men; the cop who showed up was restrained at first but reacted to the irate professor by arresting him.
Lesson: police training needs to be drastically reformed. And training for police dispatchers, as well as from one police car to another, needs to be instructed on how rumors are formed; and procedures to avoid inflammatory worst-case clichés.
 Racism among police. Some cops are racists.