What would it take to make you feel justified in killing someone?

I suspect everyone has their threshold. Some are as pugnacious as a peevish polecat and would shoot someone over a disputed parking spot. Others are such pacifists they would let a burglar kill them and their entire family before they would take the murderer’s life. But when we start ratcheting up the potential mayhem, most of us hit our take-a-life threshold.

If a crazed terrorist were about to detonate a hydrogen bomb and kill everyone in New York City, and you had him in the cross hairs of a sniper rifle, would you take the shot? Bear in mind he’s about to kill himself in the attack, so it isn’t as if you would be preserving his life by refusing to fire. By not shooting, you’d just be ensuring that 10 million innocent people died with him.

If 10 million lives isn’t enough incentive, how about a crazed scientist who has rigged the entire planet to explode killing himself and every other living thing on Earth? Would that be enough to shake the pacifism? What sense would it be to spare the life of a man who’s going to blow himself up if you do not act?

Where’s your kill threshold? What, in your mind, justifies taking the life of another human being?