I should point out that Oakland is run by the Democratic Party the order to clear the OWS people out of Oakland was given By Jean Quan the Mayor of Oakland and a member of the Democratic Party in fact most of the places that the OWS crowd is camping out in America are in places that are run by the Democratic Party like Portland Oregon where there has been a OWS protest in fact New York City where the OWS movement started is run by the Democratic Party so there is no way anybody on this site can blame the riot in Oakland on the Republicans because they are in charge in Oakland.
Did anyone mention the GOP or the Dems? If they did I missed it. I don't think the extreme polarisation of United Statesian politics has infected this site.
But if you want me to mention something about it I will.
Politicians are corrupt. Small fry United Statesian politicians (mayors etc.) are probably more corrupt than most. There's hardly any difference between the two parties at that level (despite what "some" might say). Jean Quan may ride a donkey but that's because that's the only way she could get elected in a city like Oakland.
And you can bet your bottom dollar that the police departments in all the cities you mention are not staffed by pot-smoking, peace-loving hippies, either. That's just the way of police departments in general, but it seems to be more pronounced in the United States. So I'd say it's the heavy-handidness of the officers on the ground that's the problem here - not who ordered them in.