"and there is a very high likelihood that such a law would be ineffective due to the basic nature of the powers a city needs to govern itself" I think this is

"and there is a very high likelihood that such a law would be ineffective due to the basic nature of the powers a city needs to govern itself" I think this is not true. You haven't made any reasonable arguments in this regard - i.e. haven't demonstrated how a) the law could not be enforced or b) how the city needs to subsidize in order to function A law banning direct corporate subsidies would work really well. "The crafting of such a law without destroying the governance of a city" I totally disagree. Cities generally do not directly subsidize businesses. As for getting the law passed, yes, I'm with you there. Very hard. It couldn't be done at a state level because states compete, so it'd have to be done at the national level.