In practice how it works in most large cities in the US is the mayor ends up deferring to police leadership because the police hold so much influence over local political conditions. Mayors that get tough on dirty cops find themselves riding a wave of crime atop the police deciding to simply stop policing certain sorts of calls or in particular areas.
>>jasonw+(OP)
Ah now that makes sense. Like most management jobs you don't really have as much power as you think you have. You need developers to be on your side otherwise you no going to achieve much with your team fighting you.