So could they have an H-bomb? Well, why not? If they don’t have two-stage weapons yet—that is, if they are “just” boosting fission weapons with small amounts of fusionable materials—they will soon. Because this is the kind of thing that states who test lots of nuclear weapons are capable of doing, eventually. And at some level, it hardly matters: If they can pull off 100 kilotons, then you might as well treat them like they have an H-bomb. Because it’s good enough. Even 20 kilotons, which is what they were estimated to have as of a year ago, is enough to cause enough destruction that it wouldn’t be worth risking except in the most dire of circumstances.

What about their missiles? Contrary to the technology tree of the Civilization game series, intercontinental ballistic missiles (ICBMs) came after thermonuclear weapons, but only by a few years. We are rapidly approaching the 60th anniversary of the Soviet Union’s launch of Sputnik, the first satellite, which was put into orbit on top of the R-7, the first ICBM. So this isn’t brand-new technology, either. To be sure, rocket science is, to some degree, still “rocket science.” Even Elon Musk’s rockets still occasionally blow up, and nobody doubts the competence of his engineers. Both the American and Soviet rocket and space programs suffered terrible accidents, and the number of things that can go wrong in a “real-world” application of missiles is, well, astronomical. And yet, with effort, these sorts of things largely get figured out. North Korea’s tests haven’t been universally successful (which may be because of sabotage, or just because it is legitimately hard), and there are debates among experts as to what kind of missile range we can expect them to currently have, but it’s clear they’re putting a lot of effort into it, and if they aren’t currently capable of hitting the continental United States, they will be, soon. They almost certainly can hit closer targets that we value, such as Japan, and potentially even Hawaii.

Nuclear deterrence doesn't require mutually assured destruction. It's easy to think this if you were raised with the idea that nuclear deterrence is about the United States versus the Soviet Union or Russia, two countries with huge arsenals encompassing over 90 percent of the world’s nuclear weapons.

North Korea can’t destroy the United States. It could, however, cause us a lot of hurt. A nuclear-armed North Korea doesn’t have to change much: Just don’t box them into a corner, stay firm on what is truly unacceptable behavior, and be willing to compromise for mutual benefit. We shouldn’t find living in the nuclear age any more anxious than it has been for the past many decades: North Korea isn’t demonstrably “crazier” than the People’s Republic of China was during the heyday of its Cultural Revolution when it went nuclear, and our situation, while nerve-wracking, isn’t more existential than it was during the 1980s. The nukes of the Cold War haven’t gone away, and adding one more country to the list—while definitely not an optimal situation—isn’t going to change much. One hopes that our military leaders understand this, because if history is any guide, the most likely path to nuclear war won’t be outright aggression, but a comedy of tragic errors, misunderstandings, and miscommunications.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.