> The actual, intended purpose, in a functioning society, is to {serve fair punishments and rehabilitate, enhance quality of health, etc}.
I'm not sure which history books you've been reading, but modern police were invented in the 17th and 18th centuries as brutal forms of population control. In America, the "actual, intended purpose" was to be a genocidal force that clears the land of Amerindians, to patrol the slaves, to terrorize the workers, and so on. In the South, you can trace the history of police departments directly to Confederate troops, who, immediately after losing the war, rounded up people and threw them in prison on fabricated charges. To a lot of people, it was as if the war never happened. The fact that there was no reign of terror in the south tells you everything you need to know. And the slavery continues to this day. So I have no idea what you mean when you talk about this fantastical "intended purpose".