In October 1974, Henry A. Kissinger, the US secretary of state, met with Soviet leader Leonid Brezhnev in Moscow to discuss unresolved arms-control matters before the upcoming US–Soviet summit in Vladivostok. They made progress but still noted that détente – the finely calibrated reduction of US–Soviet tensions that their two governments had presided over in the previous few years – was in fact “hanging by a thread.” Both men knew only too well what the alternative would be. As the recently resigned US president, Richard M. Nixon, had warned Brezhnev a few months earlier: “if détente unravels in America, the hawks will take over, not the doves.”

Eventually they did. By the end of 1980, US–Soviet relations were freezing, with few economic transactions, daily exchanges of hostile words, and growing concerns among American and Soviet citizens about their countries’ military competition. Since détente was motivated by a desire to stabilize the nuclear arms race, enhance bilateral cooperation, and decrease the ideological and geopolitical rivalry between the superpowers, its fate was increasingly apparent.

The collapse of superpower détente did not happen overnight. Nor was it caused by a single, overwhelming destructive force, like an earthquake or tsunami. Rather, it was a slow, eroding process, in which multiple events and forces added strength to one another and gradually tore apart the delicate fabric of lofty ideas, pragmatic assumptions, and half-sincere obligations associated with détente.