[T]he North owes its security not to nuclear weapons, but to American fears that even a minor strike on the North would result in devastating retaliation against Seoul. Any consistent outward improvement of inter-Korean relations naturally casts doubt on the automaticity of such retaliation and therefore undermines the North's security. The consequence is that the Kim regime must walk a tightrope. On the one hand it must project reasonableness and an openness to negotiations, while on the other it has to project great volatility and excitability, a readiness to stop at nothing.