I would bring back public execution for especially heinous crimes where there is no doubt of guilt.
An example: A person caught in the act literally committing sexual assault on a child.
Obviously there would be circumstances where it was not appropriate. Such as if the crime is committed by a disabled person or a minor or someone incapable of understanding reason. But for the most part— People caught doing horrible things to other people would be subject to public execution. It would send a clear warning that our society will not tolerate this behavior under any circumstances. And that the punishment for doing something so unspeakable is death.