Because the US has control of the sea. Because the US has built up its wealth. Because the US is the only country in the world really not to have a war fought on its territory since the time of the Civil War ... Therefore we can afford mistakes that would kill other countries. And therefore we can take risks that they can't ... the core answer to why the United States is like this is we didn't fight World War I and World War II and the Cold War here.

If you go through the list of things that are not possible you're left with a very finite amount of possibilities. The fancy name for this is constraint theory. It's a nonquantitative model, but it's a field of mathematics.

It has always struck me as the world's great fortune that the two great superpowers were the United States and the Soviet Union, who managed the Cold War with meticulous care in retrospect. Imagine the European diplomats of 1914 or 1938 armed with nuclear weapons. It is easy to believe they would not have been as cautious.

In a way, we can have a much easier discussion about the future of technology than we can about why a young man kills another man in a war.

While certain coastal cities have become very prosperous, the rest of China has a per capita income of $200 a year. The coast wants to have nothing to do with the interior; it wants to work with Tokyo and New York. This is an old story in China. It is why Mao succeeded in 1927. He wanted [coastal] Shanghai to throw the foreigners out, but Shanghai was doing too well financially [to expel foreigners]. So Mao went to the interior and raised a peasant army. He came back to Shanghai and sealed off the country.

What is revolutionary today is that we're using precision-guided munitions. And instead of building individual weapons, we are building an industry and a philosophy, the culture of precision. You saw Desert Storm. Precision works.

By the 20th century, war ceased to be an encounter between two armies. It became an encounter between two societies, because a factory worker producing a gun or a bomb is as deadly as a pilot.