Imagine that you’ve learned in your local newspaper and on TV that a serial murderer is stalking and killing people in your community. Anxious and concerned for the safety of your family, you buy a gun.
Then your worst nightmare happens. Lying in bed and drifting off to sleep, you hear a loud sound downstairs – the unmistakable explosion of your front door being battered down and the menacing footsteps of an intruder climbing the stairs to your bedroom. You cock your already-loaded gun, and when the thug lunges at you, you shoot.