I live in MI and state law here allows a dog to bite someone threatening the owner and/or the property of the owner. State law also allows a dog to bite a person who has repeatedly harassed or menaced the dog, but you have to be able to prove it. However, the "victim" can still sue in civil court. It usually helps if the criminal courts have already handed down a guilty verdict. Basically, this means that a dog won't be declared dangerous/vicious or put down but the owner can take a hit to their pocketbook.