In the 80s, the Soviet Union built a system of sensors and failovers scarily close to an automated “dead-man’s switch” that would ensure the launch of their nuclear arsenal even if a US first strike destroyed their command and control, or even most of their cities and population. They called it Perimeter, and it’s actually still in place.

Perimeter ensures the ability to strike back, but it’s no hair-trigger device. It was designed to lie semi-dormant until switched on by a high official in a crisis. Then it would begin monitoring a network of seismic, radiation, and air pressure sensors for signs of nuclear explosions. Before launching any retaliatory strike, the system had to check off four if/then propositions: If it was turned on, then it would try to determine that a nuclear weapon had hit Soviet soil. If it seemed that one had, the system would check to see if any communication links to the war room of the Soviet General Staff remained. If they did, and if some amount of time—likely ranging from 15 minutes to an hour—passed without further indications of attack, the machine would assume officials were still living who could order the counterattack and shut down. But if the line to the General Staff went dead, then Perimeter would infer that apocalypse had arrived. It would immediately transfer launch authority to whoever was manning the system at that moment deep inside a protected bunker—bypassing layers and layers of normal command authority. At that point, the ability to destroy the world would fall to whoever was on duty: maybe a high minister sent in during the crisis, maybe a 25-year-old junior officer fresh out of military academy. And if that person decided to press the button … If/then. If/then. If/then. If/then.

Once initiated, the counterattack would be controlled by so-called command missiles. Hidden in hardened silos designed to withstand the massive blast and electromagnetic pulses of a nuclear explosion, these missiles would launch first and then radio down coded orders to whatever Soviet weapons had survived the first strike. At that point, the machines will have taken over the war. Soaring over the smoldering, radioactive ruins of the motherland, and with all ground communications destroyed, the command missiles would lead the destruction of the US.

The older I get, and the more I reflect on the Cold War era of nuclear detent, the more shocked I am to still be alive in a green and living world.