As one advances in age, one tends to mark each new year by reflecting on the broader developments that have run in parallel with one's own lifetime. For my part, I usually focus on the surprises: things that would have been considered unlikely or even unimaginable in my younger years.
I was born during World War II and grew up in Canada with a general awareness of at least some aspects of the larger world, not least the Cold War. Television allowed us to witness the destructive power of nuclear weapons from our living rooms. I and many other children had watched "Our Friend the Atom" on the television series "Walt Disney's Disneyland," but we nonetheless would lie awake at night listening to passing planes, hoping they were not bearing the instruments of our annihilation.
The nukes were kept in their silos, owing to the deterrent effect of "mutually assured destruction" and the effective leadership shown during close calls like the Cuban Missile Crisis. Eventually, the Cold War ended and anyone under 30 has spent their entire life in a world without it. To most of them, U.S. economic and military primacy probably seems as ordinary and permanent as the Cold War did to baby boomers. But now we are on the verge of another anxiety-inducing shift in power relations.