In the early 1980s, when President Ronald Reagan fired up his rhetoric about the Evil Empire, top Soviet military and intelligence officials took him seriously. Believing that Reagan might attempt a nuclear surprise attack, they gave their intelligence outposts in the West orders to hunt for any hint that a missile attack might be imminent.
One directive ordered Soviet spies to track the price of blood, on the shaky theory that authorities would purchase large blood supplies in preparation for war. Another required officers to monitor lights on at night in key government buildings in Western capitals, according to Christopher Andrew and Oleg Gordievsky's lively 1991 history, KGB: The Inside Story (HarperCollins, 832 pages, $20).
From such slender reeds hung the fate of the world. The orders from Moscow "contained deep passages of black comedy, which revealed terrifying gaps in the [KGB] Center's understanding of Western society," write Andrew and Gordievsky, a KGB defector.
Thus might a few late nights for Pentagon workers laboring to figure which millions should go to which defense contractors have persuaded Soviet leaders to strike before the Americans could complete what looked like feverish planning for war.
So what was the problem? Not enough turncoats! If only more Americans well-placed in the U.S. government had been feeding information to Moscow, Soviet leaders would have known there was no chance of an American first strike. Surely that would have made the world a safer place.
The inescapable conclusion: Blessed are the traitors, for they helped prevent nuclear holocaust.
It's not a sentiment often expressed in the massive literature of espionage in the second half of the 20th century. But a serious case can be made that one reason the Cold War remained cold for four decades was that many people on both sides saw fit to sell their country's secrets. And the case is not undermined by the repugnant nature of traitors or by the destruction they caused.
Those who spied for the enemy were often despicable human beings -- mercenary, manipulative, egotistical, spendthrift, alcoholic and often downright weird. Consider FBI mole Robert Hanssen, a member of the conservative Catholic organization Opus Dei, who set up a secret video camera so a friend could watch Hanssen have sex with his wife.
"He betrayed his country and simultaneously betrayed his wife," David Wise writes in Spy: The Inside Story of How the FBI's Robert Hanssen Betrayed America (Random House, 310 pages, $24.95). "And all the while he was confessing his sexual sins, and his espionage, to his priests, piously observing the rules and rites of Opus Dei, and urging his friends to get closer to God."
Many traitors revealed the names of secret agents working for the other side, prompting their imprisonment or execution. CIA agent Aldrich Ames, who worked secretly for the Soviets and Russians for nine years, betrayed some 30 Western agents, at least 10 of whom were executed, according to the invaluable Spy Book: The Encyclopedia of Espionage, by Norman Polmar and Thomas B. Allen (Random House, 633 pages, $30).
Some double agents gave away military and intelligence operations that cost hundreds of millions of dollars to replace. Former National Security Agency analyst Ronald Pelton, for instance, revealed to the Soviets in 1980 that the United States was tapping into Soviet communications cables on the floor of the Sea of Okhotsk. With a single conversation, Pelton undid a colossal investment and obliterated a valuable source of data on Soviet intentions.
Finally, if war had broken out, as World War II had shown, the agents' work would have put the country they betrayed at a potentially catastrophic military disadvantage. The enemy would have had secret war plans, locations of nuclear missiles, code books and more.
But war did not break out. And spying was one of the reasons.
Like parasites in a natural system, spies are not the prettiest of creatures. But they redress imbalances, curing paranoia with information.
In the standoff of the United States and Soviet Union, double agents increased confidence that the other side was not about to launch a first strike -- no matter how late night lights were burning. By revealing the adversary's military capabilities, they also discouraged both sides from imagining they could survive a nuclear exchange. In the doctrine of mutual assured destruction, the turncoats on both sides were often the chief assurers.
American accounts of the likes of Hanssen and Ames naturally emphasize their perfidy, treating them with a degree of hatred and contempt otherwise reserved for child molesters. But from the Soviet viewpoint, they were heroes whom the KGB often rewarded with official military rank and decorations.
To get some perspective on the Americans who spied for the Soviet Union, it's useful to consider their mirror image: Russians who provided Soviet secrets to the United States. Their story is thoughtfully told by veteran CIA officer John Limond Hart in The CIA's Russians (Naval Institute Press, 225 pages, $28.95).
Hart's book underscores the courage of Soviet citizens who dared to betray their country. Some were motivated by their hatred of the totalitarian regime. But it is clear that many had the same foibles, egotism and greed as their American counterparts.
Take one of the first, Col. Pyotr Popov of the GRU, Soviet military intelligence, who fed information to the CIA from posts in Vienna and Berlin from 1953 until 1958, when he was found out and executed.
Hart portrays Popov as a mediocre Soviet officer of peasant origins who felt his superiors looked down on him. His treachery was largely motivated by money: He had a mistress to support as well as a wife and children. CIA cash paid for his mistress' three abortions.
Yet whatever his personal shortcomings, Popov was considered important to the CIA since he could provide early warnings of hostile intentions on the part of the large and somewhat unpredictable Soviet army in Europe, Hart writes. Fearing a Korean-style sneak attack, the CIA was deeply grateful for Popov's evidence that no such escapade was planned.
In his new collection of essays, Intelligence Wars: American Secret History From Hitler to al-Qaeda (New York Review of Books, 450 pages, $27.95), Thomas Powers notes that eventually much of what the United States and the Soviet Union learned of each other's arsenals came from satellites. But the best dope on the other side's intentions could come only from human intelligence provided by all-too-human traitors.
"From the emerging history of intelligence in the Cold War," writes Powers, "we learn that an arms race can be stable, and Great Powers can struggle vigorously for decades without precipitating a global bloodbath, so long as both sides are good at discovering, but not too good at hiding, the secrets that really count."
For the low-brow version of the same shrewd observation, we can turn to John A. Walker Jr., the U.S. Navy officer who led the family spy ring that sold an astonishing variety of codes and military secrets to the Soviets over 18 years.
"We let the Russians read our mail just like we read their mail," the imprisoned Walker told Pete Earley for his 1988 book, Family of Spies: Inside the John Walker Spy Ring (Bantam, 466 pages, $4.95). "That's it. That's all. The United States monitors every international telephone call and open circuit in the world. All I did was sell those poor bastards the same access."
Scott Shane, a reporter for The Sun since 1983, has covered intelligence and served as Moscow correspondent from 1988 to 1991. His book, Dismantling Utopia: How Information Ended the Soviet Union, is available in paperback.