found in an old social psych book:

Innocent victims tigger more compassion if personalized. In a week when a soon-forgotten earthquake in Iran kills 3000 people, a lone boy dies, trapped in a well-shaft in Italy, and the whole world grieves. The projected death statistics of a nuclear war are impersonal to the point of being incomprehensible. So international law professor Roger Fisher proposed a way to personalize the victims:

"It so happens that a young man, usually a navy officer, accompanies the President wherever he goes. This young man has a black attache case which contains the codes that are needed to fire nuclear weapons.
I can see the President at a staff meeting considering nuclear was as an abstract question. He might conclude, 'On SIOP Plan One, the decision is affirmative. Communicate te Alpha line XYZ.' Such jargon keeps what is involved at a distance.
My suggestion, then, is quite simple. Put that needed code number in a little capsule and implant that capsule right next to he heart of a volunteer. The volunteer will carry with him a big, heavy butcher knife as he accompanies the President. If ever the President wants to fire nuclear weapons, the only way he can do so is by first, with his own hands, killing one human being.
'George,' the President would say, 'I'm sorry, but tens of millions must die.' The President then would have to look at someone and realize what death is - what an innocent death is. Blood on the White House carpet: it's reality brought home.
When I suggested this to frinds in the Pentagon, they said, 'My God, that's terrible. Having to kill someone would distrot the President's judgement. He might never push the button.' "

(Fisher, R. (1981) Preventing nuclear war. Bulletin of the Atomic Scientists, March, 11-17.)