Police officers and doctors require a level of dexterity that robots cannot replicate, and doctors, lawyers and police officers require a level of conscious decision making that is unlikely for computers to be able to replicate. Lawyers create arguments based on abstract concepts, so even if a computer can learn legal precedent, it doesn't seem likely they can adapt and create novel legal arguments required to inform new areas of the law. Much of the law in the US is determined by case law, not legislative law, so it's just not likely robots will ever acquire the ability or be granted the authority to have input on such crucial items. If robots could learn to be a suitable lawyer, doctor or police officer, we would be living in a world where we are subservient to robots.