Polling suggests widespread gloom among younger Americans over climate change, while other surveys pick up foreboding in the older population at the renewed prospect of nuclear war. Vladimir Putin’s saber-rattling at the West as he rips up Ukraine has jogged memories from a Cold War era extending through the 1980s when the “Day After” was dreaded in half of America, at least. Unfortunately it is not just a rearmed and seemingly maniacal Kremlin that is stoking fear, but its diplomatic abettor, the Chinese Communist Party. As this piece in the latest Foreign Affairs by one of the U.S. military-strategy gurus lays out, Beijing’s rapid nuclear (as well as conventional) buildup is going to change the macabre calculus that has, over 75 years, kept us from doomsday. Andrew Krepinevich describes how deterrence among three nuclear superpowers is considerably more treacherous than between two. In his view, it’s going to require ever more upgrading of the American arsenal, an outcome that will not sit well with most Democrats (or taxpayers in general). This is one more tragic result of the aggressive nationalism that Xi Jinping has embodied in China, of greater consequence globally than Putin’s extortions in Europe. The U.S., though of course not without its international manipulations at all times, has a century-long record of military slouch during eras of apparent peace. That it is needlessly being called back to the battlements is a sad fact of our present.