I think the personal and psychological aspects of war remain the same. War is about killing and dying. A man or woman stands at the post and there is a very real possibility of dying in the next five minutes. Whether he dies or not depends partly on him and partly on luck, and yet he must continue to function.

There is no difference in a country between military, economic, and political affairs. It's useful for Business Insider to divide things that way. That's useful for a college program. But a country is a country. How do you understand China's economy without China's army? If you take these all into account you're ready to explain a question like, "How come the US doesn't have a debt problem?"

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.

When you have the countries like Germany, China, and Russia decline, and be replaced by others, that's when systemic wars start. That's when it gets dangerous, because they haven't yet reached a balance. So Germany united in 1871 and all hell broke loose. Japan rose in the early 20th century, and then you had chaos. So we're looking at a systemic shift. Be ready for war.

The British bombed German cities [during World War II] to keep the workers awake at night. So instead of dropping one bomb, we sent a thousand planes and, yes, we took out the factory sometimes, but we also took out the city. It reached the point where we wanted more efficient ways to destroy a city. The result was nuclear weapons.

The man who hates war more than he hates the Nazis is a wicked man.

We cannot anticipate the moral circumstances under which we will live. And therefore [I refuse] to say that I will not live in a moral circumstance that requires violence.