This month marks the fiftieth anniversary of Stanley Kubrick’s black comedy about nuclear weapons, “Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb.” Released on January 29, 1964, the film caused a good deal of controversy. Its plot suggested that a mentally deranged American general could order a nuclear attack on the Soviet Union, without consulting the President. One reviewer described the film as “dangerous … an evil thing about an evil thing.” Another compared it to Soviet propaganda. Although “Strangelove” was clearly a farce, with the comedian Peter Sellers playing three roles, it was criticized for being implausible. An expert at the Institute for Strategic Studies called the events in the film “impossible on a dozen counts.” A former Deputy Secretary of Defense dismissed the idea that someone could authorize the use of a nuclear weapon without the President’s approval: “Nothing, in fact, could be further from the truth.” (See a compendium of clips from the film.) When “Fail-Safe”—a Hollywood thriller with a similar plot, directed by Sidney Lumet—opened, later that year, it was criticized in much the same way. “The incidents in ‘Fail-Safe’ are deliberate lies!” General Curtis LeMay, the Air Force chief of staff, said. “Nothing like that could happen.” The first casualty of every war is the truth—and the Cold War was no exception to that dictum. Half a century after Kubrick’s mad general, Jack D. Ripper, launched a nuclear strike on the Soviets to defend the purity of “our precious bodily fluids” from Communist subversion, we now know that American officers did indeed have the ability to start a Third World War on their own. And despite the introduction of rigorous safeguards in the years since then, the risk of an accidental or unauthorized nuclear detonation hasn’t been completely eliminated.

The command and control of nuclear weapons has long been plagued by an “always/never” dilemma. The administrative and technological systems that are necessary to insure that nuclear weapons are always available for use in wartime may be quite different from those necessary to guarantee that such weapons can never be used, without proper authorization, in peacetime. During the nineteen-fifties and sixties, the “always” in American war planning was given far greater precedence than the “never.” Through two terms in office, beginning in 1953, President Dwight D. Eisenhower struggled with this dilemma. He wanted to retain Presidential control of nuclear weapons while defending America and its allies from attack. But, in a crisis, those two goals might prove contradictory, raising all sorts of difficult questions. What if Soviet bombers were en route to the United States but the President somehow couldn’t be reached? What if Soviet tanks were rolling into West Germany but a communications breakdown prevented NATO officers from contacting the White House? What if the President were killed during a surprise attack on Washington, D.C., along with the rest of the nation’s civilian leadership? Who would order a nuclear retaliation then?

With great reluctance, Eisenhower agreed to let American officers use their nuclear weapons, in an emergency, if there were no time or no means to contact the President. Air Force pilots were allowed to fire their nuclear anti-aircraft rockets to shoot down Soviet bombers heading toward the United States. And about half a dozen high-level American commanders were allowed to use far more powerful nuclear weapons, without contacting the White House first, when their forces were under attack and “the urgency of time and circumstances clearly does not permit a specific decision by the President, or other person empowered to act in his stead.” Eisenhower worried that providing that sort of authorization in advance could make it possible for someone to do “something foolish down the chain of command” and start an all-out nuclear war. But the alternative—allowing an attack on the United States to go unanswered or NATO forces to be overrun—seemed a lot worse. Aware that his decision might create public unease about who really controlled America’s nuclear arsenal, Eisenhower insisted that his delegation of Presidential authority be kept secret. At a meeting with the Joint Chiefs of Staff, he confessed to being “very fearful of having written papers on this matter.”

President John F. Kennedy was surprised to learn, just a few weeks after taking office, about this secret delegation of power. “A subordinate commander faced with a substantial military action,” Kennedy was told in a top-secret memo, “could start the thermonuclear holocaust on his own initiative if he could not reach you.” Kennedy and his national-security advisers were shocked not only by the wide latitude given to American officers but also by the loose custody of the roughly three thousand American nuclear weapons stored in Europe. Few of the weapons had locks on them. Anyone who got hold of them could detonate them. And there was little to prevent NATO officers from Turkey, Holland, Italy, Great Britain, and Germany from using them without the approval of the United States.

In December, 1960, fifteen members of Congress serving on the Joint Committee on Atomic Energy had toured NATO bases to investigate how American nuclear weapons were being deployed. They found that the weapons—some of them about a hundred times more powerful than the bomb that destroyed Hiroshima—were routinely guarded, transported, and handled by foreign military personnel. American control of the weapons was practically nonexistent. Harold Agnew, a Los Alamos physicist who accompanied the group, was especially concerned to see German pilots sitting in German planes that were decorated with Iron Crosses—and carrying American atomic bombs. Agnew, in his own words, “nearly wet his pants” when he realized that a lone American sentry with a rifle was all that prevented someone from taking off in one of those planes and bombing the Soviet Union.

The Kennedy Administration soon decided to put locking devices inside NATO’s nuclear weapons. The coded electromechanical switches, known as “permissive action links” (PALs), would be placed on the arming lines. The weapons would be inoperable without the proper code—and that code would be shared with NATO allies only when the White House was prepared to fight the Soviets. The American military didn’t like the idea of these coded switches, fearing that mechanical devices installed to improve weapon safety would diminish weapon reliability. A top-secret State Department memo summarized the view of the Joint Chiefs of Staff in 1961: “all is well with the atomic stockpile program and there is no need for any changes.”

After a crash program to develop the new control technology, during the mid-nineteen-sixties, permissive action links were finally placed inside most of the nuclear weapons deployed by NATO forces. But Kennedy’s directive applied only to the NATO arsenal. For years, the Air Force and the Navy blocked attempts to add coded switches to the weapons solely in their custody. During a national emergency, they argued, the consequences of not receiving the proper code from the White House might be disastrous. And locked weapons might play into the hands of Communist saboteurs. “The very existence of the lock capability,” a top Air Force general claimed, “would create a fail-disable potential for knowledgeable agents to ‘dud’ the entire Minuteman [missile] force.” The Joint Chiefs thought that strict military discipline was the best safeguard against an unauthorized nuclear strike. A two-man rule was instituted to make it more difficult for someone to use a nuclear weapon without permission. And a new screening program, the Human Reliability Program, was created to stop people with emotional, psychological, and substance-abuse problems from gaining access to nuclear weapons.