One of the issues we've seen is that the police act as a political organisation. It's a message from the Police: "Look at these looters, you need us". They use their position to push for the political outcome they want. Similarly you can elect a mayor who will reform the police, but what's likely to happen is that the police just tweak their behaviour to allow an increase in crime so that come next election, the mayor's "reforms" have made his citizens less safe and you get rid of the mayor - because the police aren't accountable, the mayor is. An institutional interest has emerged and really the only way of changing that is to remove the institution and replace it.