Jeffrey Lewis and Aaron Stein write:

Our reading of most nuclear crises from the Cold War is that, while both Washington and Moscow sought to avoid the use of nuclear weapons, there were always opportunities — by misperception, accident, or simply chance — for the nuclear powers to stumble into a nuclear war neither side wanted. Many officials in the Kennedy administration were confident that Soviet leader Nikita Khruschev would seek to avoid nuclear war under any circumstances, even if the United States were to invade Cuba. They were also certain that there were no Soviet nuclear weapons in Cuba. On the latter point, they were wrong. These kinds of historical near-misses may send a shiver down one’s spine, but that is precisely the point. Without the risk that something might go horribly wrong, nuclear deterrence would cease to function. For a world leader to feel the pinch of nuclear deterrence restraining her, she must believe that at some point things might go catastrophically wrong.

Tom Schelling argued that analysts were mistaken to talk of the brink of nuclear war as if it were the “sharp edge of a cliff where one can stand firmly, look down, and decide whether or not to plunge.” A better description, he argued, was a “curved slope.” A leader might edge his or her country out onto this slope, but “the slope and the risk of slipping are rather irregular; neither the person standing there nor the onlookers can be quite sure quite how great the risk is, or how much it increases when one takes a few steps downward.”

The United States and Russia have edged, ever so carefully, out onto this slope. The Biden administration, for example, carefully weighed the risks of providing rocket systems to Ukraine that can strike targets on the Russian side of the border before deciding, correctly in the authors’ view, that such systems should be provided. This step seems safe enough. But we should acknowledge that we do not really know and that there remains a risk of slipping. Tread carefully. [Continue reading…]