I think, with proper care, this dog can be rehabilitated. Sure, it's a killer.. so what? It's an individual! None of us know what a hard life it might have had early on in the litter, how the big pup might have picked on it.
Put it in a correctional institution, give it a chance to interact with other prisoners, get some regular exercise, watch a little TV. Than move it on to a half-way house when the parole board decides it is ready. If it does well there, give it back to Princess Anne and let it rejoin society as a useful companion pet.
You folks seem pretty anxious to send it to the chair, with some even promoting doggy genocide against an entire breed.