For as long as there are men to whom power is everything – i.e., as long as there are men – there will be a need to make them feel vulnerable. Nothing does the job nearly as well as the thought of a nuclear warhead falling straight down at their heads. To reject that device – that leash that pulls the dictator irresistibly onto the same battlefield as his armies – is to reject the most effective peacekeeping instrument Mankind has yet devised.
I'll paraphrase a bit. As long as there are men, there will be men to whom power is everything and they will need to be controlled. I think this is one of the great truths that "modern" man wants to deny. Modern man would rather think we can all get along or we can negotiate or we will act rationally. This just isn't true. There will always be some men who will not get along, they will not negotiate and they will not act rationally. They must be made to feel vulnerable.