If the Britain and France had done what they were obliged to do under the treaty and sent troops to enforce the treaty when Hitler remilitarized the Rhineland, the German general staff would have turned Hitler out. And one would not have had a cause for war, and you wouldn't have had World War II.

When a rapidly rising power rivals an established ruling power, trouble ensues. In 11 of 15 cases in which this has occurred in the past 500 years, the result was war. The great Greek historian Thucydides identified these structural stresses as the primary cause of the war between Athens and Sparta in ancient Greece. In his oft-quoted insight, "It was the rise of Athens and the fear that this inspired in Sparta that made war inevitable."

The best simpleminded test of expertise in a particular area is an ability to win money in a series of bets on future occurrences in that area.

There are two great tragedies in life: one is to fail to achieve one's grandest ambitions, and the other one is to succeed.

The fact that there are now many entities that may have some loose affiliation with a former core Al Qaeda - or who have decided to fashion themselves as an affiliate or follower in the Al Qaeda jihadist tradition - as well as groups that are just inspired by the concept that they could also be the perpetrators of mass killing, means that there is a spectrum of threats.

If the Britain and France had done what they were obliged to do under the treaty and sent troops to enforce the treaty when Hitler remilitarized the Rhineland, the German general staff would have turned Hitler out. And one would not have had a cause for war, and you wouldn't have had World War II.

One of the three big factors that count against war in the relationship between China and the U.S. are, first, nuclear weapons and even a condition of mutual assured destruction. Secondly, one's got two economies that have become so deeply interlaced that a war between the U.S. and China would leave Wal-Marts empty and Chinese factories producing for nothing. Thirdly, climate - if between the two of us, we keep doing what we're doing, we can create a climate in which our grandchildren won't be able to live.