In January, I started writing a novel in which a 10-kiloton nuclear bomb was detonated in the center of Washington, where I live. It was meant to be funny. I had read a 2011 report by the Federal Emergency Management Agency that described the effect of such a detonation, and was surprised to learn that my apartment in Adams Morgan would most likely survive the initial blast.

I imagined myself and my neighbors — about half wealthy millennials and half older people who’d bought in before the neighborhood’s property values skyrocketed — sheltering in awkward place in a basement, bickering over scraps of food and someone’s private stash of LaCroix cans.

Then, in April, Kim Jong-un of North Korea released a propaganda video of his army striking the Capitol; over the summer he tested intercontinental ballistic missiles that may be capable of striking the East Coast. More recently, President Trump called Mr. Kim “short and fat,” and now, apparently, North Korea has sentenced Mr. Trump to death in absentia. Suddenly, my novel started feeling a lot less funny.

For 1980s babies like me, nuclear war has long had a darkly comic edge. Too young to have experienced 1950s school drills or to remember the heightened anxieties of the early 1980s, we’ve viewed nuclear war as a terrifying improbability, especially compared with the terrifying certainties that we know all too well: global warming, terrorism, lone-wolf gunmen. America is in the privileged position of having inflicted nuclear casualties, not suffered them — and since the Cold War ended, it’s felt relatively likely that we wouldn’t be on either side of that equation again.