The kind of president we need has little to do with ideology and more to do with a willingness to wield power to moral ends.

There is a radical and unprecedented shift [in war] that is part of the general transformation of civilization. First, understand that the past 150 years of warfare are totally unprecedented in that we introduced a breathtakingly inefficient technology: guns. In the First World War, and this is not an exaggeration, it took 10,000 rounds of ammunition to kill one person. Any given shot had a one in 10,000 probability of ending someone's life.

Idealism is frequently another word for self-righteousness, a disease that can only be corrected by a profound understanding power in its complete sense.

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.

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

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.

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.