That which is asserted without evidence can be dismissed without evidence. You of all people have no excuse for reasoning this poorly and unscientifically.
The only thing that you have provided any evidence for is the trivial fact that authority can be and has been abused. You certainly haven't demonstrated that authority has been abused to the level that you assert. You make a number of extremely broad assertions about the nature of the personnel in the US police force, and it's implications, (ie, that a bribe could easily effect a coup or significant change in policy) which are not supported at all.
Yes, there are many documented cases of police corruption and illegal activity, but no real world system is ideal, so this is to be expected. Information about individual cases of brutality are scientifically meaningless if we want to draw any conclusion about the overall level of effectiveness of the police or their overall dedication to objectively upholding the law. This is a biased selection BY DEFINITION.
Furthermore, we know that maintaining a police force is both necessary and extremely challenging due to the aforementioned physiological problems with authority and the fact that a large number of persons must by employed for this purpose at a reasonable cost. Significant data would have to be acquired before we could say how well our nation had succeed at this task or even establish a baseline for success relative to our nation's level of prosperity. We know that many nations have done far worse at this task, corporation being particularly problematic in South America, Africa, India and China, due to a lack of bureaucratic infrastructure. [1]
You have the educational background to know that what you have been posting is not reasoning that can support itself. Doing what you have done is destructive both to analysis of the subject at hand as well as to the promotion of scientific thinking. You do not have the excuse of ignorance. Shame on you.
[1]
http://en.wikipedia.org/wiki/Corruption_Perceptions_Index