Poor Fail-Safe. Released 50 years ago this week, it remains the redheaded stepchild, destined forever to be known as that movie that’s just like Dr. Strangelove, only not funny and nobody’s seen it.

Stanley Kubrick made sure it was so. As biographer Vincent LoBrutto describes, when Kubrick learned that Fail-Safe was in the works and had a nearly identical plot, he sued to stop its production, alleging plagiarism. He eventually settled for having the film shelved until his own left theaters. By the time Fail-Safe debuted, Dr. Strangelove had already ascended to the pantheon as the definitive protest film against the nuclear age. After its dark comedy, who could bother with this last gasp of the phony-voiced melodramas? Fail-Safe bombed at the box office, and even its star, Henry Fonda, said he couldn’t have played the role straight if he’d seen Strangelove first.

This is too bad, because as brilliant and grotesquely funny as Dr. Strangelove is, the neglected Fail-Safe is the more mature and damning take on the nuclear enterprise. It feels like it could have really happened, and it’s terrifying as a result.

Directed by the prolific Sidney Lumet (of 12 Angry Men and Network), the film depicts a nuclear attack launched accidentally by the United States against the Soviet Union. The strike order comes not, as in Strangelove, from a rather overeager general, but from a malfunctioning machine. Otherwise, the broad outlines of the movies are the same.

In the early ’60s, before the four-minute wham-bam-thank-you-ma’am of the intercontinental ballistic missile, the bombs still had to be delivered by plane. So we get to watch two hours, shown basically in real time, of the military command trying to stop the attack, the president trying to gain the trust of the Soviet chairman, and the bomber crews, convinced that war has already begun, trying to make good on their orders.

In both films, the leaders of the great powers, facing their first nuclear encounter, must negotiate awkwardly to avert the great climax. The president must convince the Russians not to launch a counterattack, and the two sides must trade technological secrets if they are to destroy the planes. Both sides have to quell mutinies from commanders who can’t bring themselves to cooperate in this sabotage, and from advisers who want to launch an all-out attack.

In many ways, Fail-Safe’s warning about the likelihood of a nuclear mishap is vindicated by Eric Schlosser’s stunning 2013 book Command and Control, which details the U.S. nuclear weapons program’s decades of jarringly lax safety standards, with scores of accidents that nearly resulted in detonation. The movie was met with criticism from military analysts on technical grounds, but whatever the particulars, Schlosser’s book pretty well bears out the broader message. One U.S. general attributes the lack of any inadvertent detonation so far to “skill, luck, and divine intervention, and I suspect the latter in greatest proportion.”

Fail-Safe is often misread as Frankenstein or Jurassic Park: the familiar whine about science’s unintended consequences and technology gone mad. But the crisis’s real cause is the logic of the nuclear system at every level—its institutions, structures, procedures, and rationales. This isn’t a movie about why we should fear machines or the people who control them. It’s about how managerial systems can bring about just the things they’re designed to avert.

Like the human members of the nuclear system, the machine that sends the launch code just follows orders, or tries to. But nobody has thought through what happens when orders are followed poorly—or too well. The American bomber commander, for example, must carry out his attack order even if he cannot verify it by radio, since radio loss could mean that home has been destroyed. He cannot be recalled even when successfully contacted by the president, or his own wife, as he’s been trained to regard these as impostors. Even the leaders are bound: They must counterstrike, even when convinced they’ve been attacked by mistake.

Where Dr. Strangelove’s subversiveness comes from its suggestion that the military leadership gets off on the prospect of nuclear war, Fail-Safe makes clear that none of its characters wanted the attack. The closest thing to an antagonist is professor Groeteschele. Like the titular Dr. Strangelove, he is philosophically drawn from Herman Kahn, the man who created the theory of nuclear strategy, of acceptable losses in millions of deaths. Early in the movie, he slaps and berates a woman who finds the idea of mass demise erotic. “I’m not your kind,” he tells her. He isn’t driven by bloodlust, just blood logic, and the moral indemnity of reason.

The general decency of Fail-Safe’s characters can make it seem naive, especially next to Dr. Strangelove. The film even shows the Americans and Russians forming friendships as they work together through the crisis. But the comparison really shows why the movie is so chilling. Its gobsmacking upshot is that the people in charge could actually be good and well-intentioned—and they’d carry out the destruction just the same. All of the personnel Schlosser interviewed seemed genuinely, soberly committed to averting war. And yet … under the principle of deterrence, their determination to avoid the nuclear holocaust also required an absolute commitment to bring it about if they were ordered to.

Lest I too be charged with excess earnestness, I should make my love plain. Catch me in person sometime and I’ll do for you the whole scene from Strangelove where President Muffley has to explain to the Russian premiere that one of his generals “went and did a silly thing.” It may be the best satire ever made. But it’s so effective that it risks being self-defeating. By the end of this farce, we’re practically giddy to see the world go up in flames.

Fail-Safe does not offer the catharsis of total destruction. And it doesn’t let us off the hook by showing that the folly belongs to the men in power, rather than to something we’re all complicit in creating. I won’t spoil the ending except to say that it involves a decision that, once revealed, is obviously the only rational one under the circumstances but causes you to draw back in horror and think that there must be some better way. And once there was—but the other choices were foreclosed before the film begins.

This article is part of Future Tense, a collaboration among Arizona State University, New America, and Slate. Future Tense explores the ways emerging technologies affect society, policy, and culture. To read more, visit the Future Tense blog and the Future Tense home page. You can also follow us on Twitter.