why nuclear weapons work as a deterrent

There’s an interesting post at Econlog that mentions Kruschev’s aversion to war, especially after he lost his own son in WWII. The discussion turned to the issue of deterrence and atomic bombs. The interesting observation is that most conventional weapons do not deter wars. The trenches, machine guns, and poison gas of WWI didn’t really make people think twice about WWII, which brought even more destruction. The threat of *millions* of deaths doesn’t make people back down, so why did nuclear weapons, specifically, seem to lead to less overall conflict between major powers?

My theory is psychological. War making is tied to an over estimation of one’s own abilities and an under estimation of the enemy. People think “my weapons are so great, and my enemies are so lame.” Even if the enemy is overwhelming, many people still resort to a vast over estimation of their own chances at survival. Hitler famously thought of some last ditch plans, even as the Soviets were shelling Berlin. The Emperor of Japan was willing to let the Japanese people suffer a million casualties as they tried to repel an inevitable American invasion. In other words, most wars allow both sides to invent a self-deceptive story of victory, even in the midst of obvious defeat.

So why nukes? Well, my theory is that it is the only weapon that effectively destroys this long shot hope with all certainty. Nuclear weapons instantaneously destroy cities and post-1945 weapons will leave decades of poisonous radiation. And there is no way to effectively prevent this. Even a Star Wars style shield won’t stop thousands of warheads, or a notorious “suitcase” nuke.There is no heroic last ditch effort in nuclear war. It’s outcome is immediate and obvious.

It’s sad, though, when the moral boundary between trench warfare and nuclear warfare is merely the speed of the carnage.