



I don't think that this is accurate. I believe, and could be wrong, that
there IS a specific right allegedly to have been violated, like the
14th or due process or whatever.


Double jeopardy does not apply, but not for the reasons you quote. Double
jeopardy states that a person may not be tried twice on the same charge.
However, the police are not on trial for the crime of excessive force
or assault. They are NOW on trial for the DIFFERENT crime of violating
Mr. King's civil rights. 

AS for the city and county or state trying you more than once, 
it most likely will not happen. This is because cities and states
have separate laws governing behaviour. For example, in some states,
it is an offence to carry marijuana, but not a city offence. Also,
I think murder is against federal, but not some state laws. 