This dilemma is named after the 17th Century political philosopher, Thomas Hobbes.
Imagine two nations who are not too far from each other, who have a strong distrust of each other. This applied to a lot of the nations near Britain at the time Hobbes pondered the question.
The first nation thinks the second is likely to attack and invade, and cause enormous harm. The second thinks the first may do the same. Both nations consider a pre-emptive strike. This is a real security dilemma. Yet if either nation actually carries out such a strike, thousands will die, and enormous destruction created. A real lose-lose situation. It gets worse. If nation A thinks nation B is more peaceful, they might consider the possibility that nation B will carry out a pre-emptive strike anyway to prevent nation A doing it first. Both nations will feel the strongest of urges to strike first.
This situation can happen on a personal level. Imagine you are at home and a burglar breaks in. You pick up a weapon, and go out to confront the burglar. Do you strike first and rapidly or not? You may not need to. You probably will not need to, since the burglar will, at this stage, mostly just want to get the hell out of there. But you may be concerned that the burglar has a weapon also, and may strike first. So do you strike to prevent the burglar being first?
In most western nations, the legal situation is that you have a right to self defense, but also a duty to exercise restraint. So if you strike first, and seriously harm or kill the burglar, you may be legally culpable. In some parts of the USA, people can strike first legally, even pulling out a gun and shooting the burglar dead, in spite of not knowing if the burglar is a threat or not.
What do you think? My view is that we all have a right to self defense, but should exercise restraint, only resorting to violence if it is clear that this is the only resort. Do you agree?