While analogies are useful, however, they can also be misleading. They smuggle in assumptions that can be wrong.

The real threat to world stability is not too much American power. It is too little American power.

In the past when a country became as powerful as the United States, other countries would band together to clip its wings. But that isn't happening now and I don't think it's not going to happen, because other countries are not threatened by us, and they secretly appreciate the services that we provide, even if they don't usually say so.

After all, the past is our only real guide to the future, and historical analogies are instruments for distilling and organizing the past and converting it to a map by which we can navigate.

American foreign policy, for all its shortcomings, has underpinned political stability around the world.

Football is controlled violence, but it is violence, which people have loved to watch since the gladiatorial contests in ancient Rome.

Certainly, protecting oppressed people, stopping ethnic conflict and promoting responsible governance are worthy goals. But none is as important for American security and prosperity as keeping the peace in the Middle East, Europe and East Asia.