Answer:
I would have to go with the state level. This is due to the varying opinions and people across the US. Going by federal law would not allow everyone to have a say since it would be by majority. The city level would be nice for freedom but overall would cause more strain trying to regulate between cities in a single state and cost much more. By using state law people have a fair weight in the saying but it won't cost more and won't leave people feeling cheated. An issue with this though would be the transfer of drugs across borders. Having legal access to drugs just across a state line is going to cause an uptick in places where they are illegal. This is however still better than costing us more money for regulation and feeling like our vote has no weight.