Cops are not doing a good job. Estimates range from 400-1000 unjustified deaths a year. To put it into context, since 9/11, there may well have been 4 times as many unjustified deaths by cops in America as unjustified deaths by Al Queda.
That isn't acceptable by any standards.
Or perhaps if you'd like, I can put it another way. There have been three times as many incidents of manslaughter and murder by American cop per capita of population than there have been incidents of manslaughter or murder in Britain in total.
That number is WAY unacceptable.
Cops carrying guns confer no benefit to those in the area (80% of bullets fired by police handguns miss their target, they don't vanish and they do hit passers-by, sound crew, hostages, etc).
Cops carrying guns confer no benefits to law and order, since alternatives from stun guns to pain rays (microwave stimulation of nerve endings, if you prefer) to teargas (which isn't great but is less lethal than a lump of lead) already exist and criminals are less likely to carry when running is a more practical option than a shoot-out. That has always been the British experience, which is why you now get regular shoot-outs where British cops are stupid enough to carry where you'd previously have had maybe one a decade versus an armed response unit.
Cops carrying guns confer no benefits to the cop, since dead weight can result a cop becoming dead, accidental shootings are very likely to produce retaliation, and "utility" belts stop utilizing when they terrify locals, intimidate visitors, but bolster thugs who gain greater mobility and dexterity from not wearing them.
Look, this is all very simple. Too simple for nutters, perhaps, but simple nonetheless.
First, preventing crime by eliminating prime environmental and psychological causes is a good start. If there's no crime, there's nobody to shoot and nobody shooting back.
Second, preventing cops turning bad by preventing them developing a "them vs us" attitude is essential and you don't achieve that by giving them scrutineering powers and not those they are scrutinizing. It has to be a two-way street to prevent that kind of mindset.
But that requires one additional ingredient to work properly:
Third, preventing cops turning bad by preventing them from being have-a-go heros. They should work with the community, be a part of the community, guard it from within. And, like all good guards, they should NOT be on constant alert. They should be constantly engaging on a social level, not a paramilitary one. If a crime happens, let the criminal go somewhere where there ISN'T a huge danger to others. Inanimate objects can look after themselves, people need a bit more effort.
It is better to let a gang "get away" from the scene, with no bullets fired, be tracked safely and then be apprehended INTACT when it is safe to do so. Going in there guns blazing will cause excessive damage, risk the lives of those supposedly protected and served, and for what? Some carcases. No trial, no determination of the chain of events, no proof even that the dead body is the guilty party. It can't exactly answer questions in the dock, can it?
No, disarm the cops, give them high-res cameras (and maybe girls gone wild t-shirts, I dunno), and let them be what cops should be - good citizens. They are NOT the army, they should NEVER be allowed military-grade weapons, they should deal with matters calmly, quietly and sensibly.
If they're not capable of that, they're incapable of good. Of any kind.