Our dogs are always leashed and well trained and we would not ever own or harbor a vicious dog or a constantly barking dog or one that while unprovoked would bite any human of any age. I'd shoot the dog myself if so as I would be the animal's responsible owner.
That said, if anyone shoots my leashed dog on my site or property or when walking on public or common grounds with the dog on a 6'max leash without being viciously attacked by my dog without having been provoked, they can be 90% sure that I would shoot them too! I/we value human life but that type of person earns and deserves exactly what they would get. NO ONE has a right to provoke another person's dog on public or private property which is under owner's control per the written laws and then shoot the animal. Don't test me!
Being attacked or viciously confronted by an unleashed dog or dogs is grounds for protecting ones self or those vulnerable in immediate danger by any means available anywhere it occurs. It's in the written statutes in most localities and/or states! You as the owner of the animal are responsible for any and all actions allowed, undertaken, or that occur by the animal you own anywhere anytime with no exceptions. Most localities do NOT require waiting for LEO personnel to be present. Even picking up after your animal on public or private property. Research it and heed.