Nepal, Sept. 15 -- I belong to a fortunate generation. Born in the United Kingdom in 1944, toward the end of a world war that killed between 70 million and 85 million people, I have neither been bombed nor had to fight on any battlefields.

I grew up in a country and continent that were at peace and thus able to enjoy the economic benefits of unprecedented cross-border cooperation. The West repelled the Soviet Union's military threat without conflict, thereby liberating its European empire to join the rest of a free continent.

In particular, Europe and other parts of the world benefitted from the leadership of the economically and militarily powerful United States. More important than America's hard power was the power of the ideas that ...