Fat Man and Little Boy, as those bombs were bizarrely code-named, should have signaled the end of nuclear war, even of all war. Some among the duck-and-cover generation feared they wouldn’t live to see adulthood, that there would be no tomorrow. Not surprisingly, too many of them, when they grew up, came to treat the planet as if there, indeed, were no tomorrow. One generation cedes to the next, doing its best to impart wisdom and offer lessons without really knowing what tools those who follow us will need to carve a better tomorrow out of a worsening today. We need not war, but peace; not new nukes, but next-generation-level diplomacy; not fossil fuels, but the greenest of powers imaginable.