Any way to prevent a nuclear war?

[Sempu]

And of course this is why the Ballistic Missile Defense System ("Star Wars") was seen as so destabilizing; it might reduce the casualties to a point where a preemptive strike would be an option.

Most people didn't understand the logic in BMD; they (correctly) reasoned that it could not intercept 100% of incoming missiles and that whatever made it through would cause catastrophic damage (also correct); so what was the point? In fact it was more game theory; the US didn't need to build a perfect BMD; all it needed to do was build a system that would cost less to knock a Soviet warhead down than it cost the USSR to make it, and they would win the arms race; the Soviets would go broke trying to keep up. This is more or less what happened anyway, only they didn't need to build the BMD to get there.