The last safeguard against a possible apocalypse, those officers were trained to unleash command missiles that would fly across the country and wirelessly deliver launch orders to any Russian missiles that had survived a first strike.
Even if the Kremlin had crumbled and all communications had been knocked out, those remaining weapons would begin the assault on the U.S.
David E. Hoffman, author of the recently-released "The Dead Hand: The Untold Story of the Cold War Arms Race and Its Dangerous Legacy," said those bunker-protected officers have been the subject of much debate.
Some argue that the good soldiers, drilled to follow orders, would function just like cogs in a machine and release the command missiles without hesitation, he said. Others maintain that they would deliberate before ordering the onset of a nuclear Armageddon.
"[They were] the so-called human firewall," he said. "They had criteria… It wasn't fully automatic."
The point of the system was not to deter the U.S. from striking, he said, but to relieve the pressure on aging leaders. He said its goal was to give leaders extra time to figure out how to respond in a crisis.
"The idea here was if I turn on the switch, I give the decision to somebody else," Hoffman said. "If I'm wiped out, I know there will be retaliation. If it's a flock of geese, I won't make a mistake."
"There was always this quest for a speedier response in an emergency," he said. "If you could get the command there faster, you could give the commander more time to think."
The Russians did consider a more frightening option: A totally automatic, computer-driven nuclear retaliation system.
Called Dead Hand, the program transferred all power to launch a counter-attack from man to machine. But the Russians ultimately rejected that system, according to Hoffman.
The most alarming piece of the equation, he said, is that the U.S. didn't know anything about it.
Notoriously secretive to begin with, the Russians were concerned that if the U.S. knew about Perimeter, they would attempt to disable it, Hoffman and others said.
"The scary part to me is that they built it and nobody knew," he said.
Although he acknowledged that given the top-secret status still attached to this program in Russia, details are hard to come by, Hoffman said that there have been some signs the Russians have started to shut down parts of the system.
But other Russian military experts say that not only is the system most likely still in place, it has received upgrades over the years.
"As far as I know, the system remains in essentially the same status as it was," said Bruce Blair, president of the Washington, D.C.-based think tank World Security Institute and one of the first to write about the Perimeter system in the early 1990s.
"The U.S. and Russia keep thousands of weapons on launch-ready alert," he said. "I think there's no reason to believe that this system would have been shut down."
Like Hoffman, he said Perimeter was intended to take pressure off of Russian leaders.
"It was a system that provided some confidence that the Soviet nuclear forces could be launched even if they didn't make a fast decision," he said. "By relieving pressure it meant that the Russians were less likely to launch a nuclear attack on false warning."
In a sense, he said, "That made everyone safer."
But, he emphasized that Perimeter's continued existence is "a symptom of a continuing grave danger."
"The fact that the Russians have Perimeter still in operation reflects that the two sides have launch on warning as their operating postures and quick launch continues to be their M.O.," he said. "We need to stand down our Cold War postures, which keep us at risk of destruction caused by false alarm or caused by unauthorized action or even by cyber-terrorism."