Theodore Roosevelt's policy to build a two-ocean navy confirmed that the old-style isolationism of the founders had not survived the modern, increasingly globalized world.
As history reminds us again and again, wars are not always made on the basis of rational calculations: often the contrary.
It is true that large parts of the world have not had to endure state-to-state wars for decades. The majority of the world's nations have also been spared the scourge of civil wars, although many have known violence from revolutionary insurrection.
Nuclear proliferation has never entirely been brought under control, and the arsenals of nuclear powers contain bombs far more powerful than those dropped on Hiroshima and Nagasaki.
As a child, I had loved history because it showed so many alternative worlds.
I still remember with gratitude a series for children on everyday life where we learned about the games children in other times had played and the food they ate.
By the start of August 1914, it was dawning on the British that a major war was about to break out on mainland Europe. Public opinion and, crucially, the cabinet was deeply divided on whether to intervene or stay out.
Are artists the canaries in the mine, warning of the coming explosion before anyone else? It's hard to look at the world before 1914 and not wonder if they somehow felt a catastrophe was bearing down on them and their societies.
I did projects on Champlain coming up the St. Lawrence River and on Henry Hudson cast adrift in the bay that now bears his name. And I read dozens of historical novels: Rosemary Sutcliff on Roman Britain and G. A. Henty on British heroes, though my all-time favourite was Ronald Welch's 'Knight Crusader.'
The cubism of Braque or Picasso, the dissonant compositions of Schoenberg or Stravinsky, the free-flowing and often erotic choreography of Isadora Duncan and Nijinsky - these were acts of rebellion against the certainties and traditions of the old world.
Some might argue humans are hard-wired to fight. I don't agree: we are conscious beings who have the capacity to make decisions.
It's not going to be easy to create a world where both sides prefer peace, but we have to try.
If a bully wants to beat you up, you have the choice of running away or standing your ground. In our society, we have police forces who try to control bullies, sometimes by force.
How curious that such an outsize man, in physique as well as personality, should be remembered today mainly for giving his name to a small fish. For the 19th century, Bismarck was no herring but a leviathan. Between 1862 and 1890, he created Germany, seeing off first the Austrian empire and then France.
George W. Bush, judging by his repeated invocations, thinks that time will eventually prove that he was right. He is not alone in putting his faith in the future.
The Canadian government has had a field day apologising for past policies towards a series of ethnic groups: Italian, Ukrainian, Sikh, Chinese, Japanese and Jews.
The act of apology is something that most societies take very seriously indeed. It is an admission of wrong done to the victims and an acceptance of blame.
No one is always right.
The only person, if you're a religious person, who's always right is God. And if you make the mistake of thinking that you, like God, are always right, and that you, like God, always know everything, then it seems to me you're riding for a fall.
Poor little Britney Spears, Lindsay Lohan, or whatever her name is. It must be incredible at that age to be surrounded by people telling you you're wonderful.
