I always think it comes down to sensuality. A bit like sexual orientation.

A guy puts his hand on your knee, and you know whether you're up for it, or not similarly.

You see the rope , the gallows, the elecric chair, gas chamber, lethal injection or whatever ... and you know whether you're up for it....stilling the flesh of another human being.

In George Orwell's famous essay The Hanging, it tells of a time when he was a young policeman in India and he had to aacompany a criminal to the gallows. On the way he watches how the man side steps a puddle, he is still capable of sidestepping the puddle. then a dog runs up to the man and covers the crimnal with licks and joyous larking about. After the hanging, the dog slinks away. Orwells comment was, even a dog knew what we were doing was wrong.

Even a dog...some people will have great reasons from the Bible on and the Koran and the Communist manifesto for using capital punishment. You can always find reasons to justify, or disagree with anything.

In the end though, it comes down to one thing ....are you up for it?