As the horror of nuclear war unfolds, will countries pull back? Will they see the destruction and say, "This is too much"? Sharon says, based on human psychology, probably the opposite.

Decision-making theories suggest that people in a situation like this where they're afraid of losing, where the safe play is to play it safe, they actually double down, and they engage in riskier behavior.

So in this scenario, in the second round, the US has expended all its nuclear weapons in Europe, so it launches 600 warheads at Russian nuclear targets, what are called counterforce targets, to try and limit Russia's ability to launch further nuclear weapons.

Because, like, without our nukes, what stops an adversary from blowing us up? Sharon says a lot of things.

We have a large conventional military, and we have it positioned in various different places, and we will hurt you.

And in the eyes of the rest of the world, your leadership is gone.

You've also probably crashed the global economy.

There are all kinds of other things.