Here's What You Need to Remember: There have been cryptic clues over the years that Perimeter still exists. Which illustrates one of the curiosities of this system, which is that the Soviet Union kept its existence secret from the American enemy whom it was supposed to deter.

Russia has a knack for developing weapons that—at least on paper—are terrifying: nuclear-powered cruise missiles, robot subs with 100-megaton warheads.

Perhaps the most terrifying was a Cold War doomsday system that would automatically launch missiles—without the need for a human to push the button—during a nuclear attack.

But the system, known as "Perimeter" or “Dead Hand,” may be back and deadlier than ever.

This comes after the Trump administration announced that the United States is withdrawing from the 1987 Intermediate-Range Nuclear Forces Treaty, which eliminated the once-massive American and Russian stockpiles of short- and medium-range missiles. Donald Trump alleges that Russia has violated the treaty by developing and deploying new, prohibited cruise missiles.

This has left Moscow furious and fearful that America will once again, as it did during the Cold War, deploy nuclear missiles in Europe. Because of geographic fate, Russia needs ICBMs launched from Russian soil, or launched from submarines, to strike the continental United States. But shorter-range U.S. missiles based in, say, Germany or Poland could reach the Russian heartland.

Viktor Yesin, who commanded Russia's Strategic Rocket Forces in the 1990s, spoke of Perimeter/Dead Hand during an interview last month in the Russian newspaper Zvezda [Google English translation here]. Yesin said that if the United States starts deploying intermediate-range missiles in Europe, Russia will consider adopting a doctrine of a preemptive nuclear strike. But he also added this:

Zvezda: "Will we have time to answer if the flight time is reduced to two to three minutes when deploying medium-range missiles near our borders? In this version, all hope is only on Perimeter. And for a retaliatory strike. Or was Perimeter also disassembled for parts?

Yesin: "The Perimeter system is functioning, it has even been improved. But when it works, we will have little left - we can only launch those missiles that will survive after the first attack of the aggressor."

It is not clear what Yesin meant when he said the system has been “improved,” or even exactly what he meant by “functioning.” Perimeter works by launching specially modified SS-17 ICBMs, which transmit a launch signal to regular nuclear-tipped ICBMs in their silos.

David Hoffman, author of “The Dead Hand,” the definitive book on Perimeter, describes Perimeter in this way:

“Higher authority” would flip the switch if they feared they were under nuclear attack. This was to give the “permission sanction.” Duty officers would rush to their deep underground bunkers, the hardened concrete globes, the shariki. If the permission sanction were given ahead of time, if there were seismic evidence of nuclear strikes hitting the ground, and if all communications were lost, then the duty officers in the bunker could launch the command rockets. If so ordered, the command rockets would zoom across the country, broadcasting the signal “launch” to the intercontinental ballistic missiles. The big missiles would then fly and carry out their retaliatory mission.

There have been cryptic clues over the years that Perimeter still exists. Which illustrates one of the curiosities of this system, which is that the Soviet Union kept its existence secret from the American enemy whom it was supposed to deter.

What is unmistakable is that Perimeter is a fear-based solution. Fear of a U.S. first-strike that would decapitate the Russian leadership before it could give the order to retaliate. Fear that a Russian leader might lose his nerve and not give the order.

And if Russia is now discussing Perimeter publicly, that’s reason for the rest of us to worry.

Michael Peck is a contributing writer for the National Interest. He can be found on Twitter and Facebook. This article is being republished due to reader interest.

Image: Reuters.