Sometime in Earth's 18th century, Eminiar VII and her sister planet, Eminiar III (Vendikar) began a war. The people of these two worlds, who were of the same species, concluded that they were killers – and that killers couldn't change. But they knew their civilization would be quickly erased by a prolonged war, so they devised a solution; a way to maintain the war, without destroying the civilization. Only the people would die.
Their war was fought entirely in the electronic circuits of two complex banks of computers – the one on Eminiar, and its counterpart on Vendikar. Several attack machines, a defense machine, and a machine to calculate the casualties were all connected by subspace relays. Although the weapons were virtual, they had very real and ominous names, such as fusion bombs and tricobalt satellites. Individuals designated as "killed" had twenty-four hours to report to a disintegration station, where they would be painlessly vaporized and their deaths recorded, all very neat and tidy. The system worked because the citizens of these planets held an ironclad social contract: stepping into a machine that would disintegrate them did not bother them. They considered it their duty to die in this way, if called on to do so, in order to prevent a real war fought with real weapons from erupting.
In 2267, the Enterprise was forced to visit Eminiar against the better judgment of Captain Kirk. Eminiar had issued a Code 710 – stay away at all costs – but the Federation very much wanted a treaty port in the sector, and so Ambassador Robert Fox ordered him in. Visiting the planet, Kirk discovered the reason for the warning: the war, which had continued for five hundred years, endangered any orbiting target. And, indeed, the Enterprise was declared a casualty, her crew required to report for disintegration. Inasmuch as Kirk had no intention of sacrificing his crew in this manner, he saw no alternative but to put and end to the war.
Kirk's analysis of Eminian society showed him the way. He and Spock began to destroy disintegration machines. As Eminiar began to fall behind its treaty-mandated disintegrations, its High Council grew more and more despondent. Finally, seizing an opportunity, Kirk took control of the High Council and its guards. Spock's fortuitous appearance moments later provided him with the final element he needed.
Spock locked the circuits of the war computers together. Then Kirk destroyed the key machine, causing the remainder of them to fail catastrophically. The link to Vendikar was dead, perhaps for the first time in centuries. Anan 7 was flabbergasted; whatever he had expected, that wasn't it, despite Kirk's claim that he could destroy the planet with just a disruptor, a claim that might be proved true. For the High Council on Vendikar could only come to one conclusion: that Eminiar VII had abrogated the treaty, and was preparing to make real war, with real weapons. Kirk, seeing Anan 7 realize this, gave him the second-best advice: start making bombs. This was followed by the best advice: consider making peace. See if, just maybe, Vendikar was every bit as afraid of real war, and every bit as willing to do anything to avoid it.
As a neutral observer, Robert Fox offered to mediate the discussions; Anan 7 led him away to a subspace link directly to the High Council on Vendikar – a link that hadn't been used in centuries. Fox's final report suggested that negotiations were underway: outlook, hopeful!
Spock, discussing it later, suggested that Kirk had taken an awful chance with the lives of two planetary populations, but Kirk didn't see it that way. He believed an actual attack wouldn't have killed any more people than a computerized attack, and it would have eliminated their ability to wage war, perhaps forever. And he considered even one attack unlikely: everything he'd seen demonstrated that the Eminians kept a very orderly society. And actual war is a very messy business. Kirk was sure the Eminians would do almost anything to avoid it. (TOS: "A Taste of Armageddon")
- "Death... destruction... disease... horror... that's what war is all about, Anan. That's what makes it a thing to be avoided. You've made it neat, and painless. So neat and painless, you've had no reason to stop it. And you've had it for five hundred years. Since it seems to be the only way I can save my crew and my ship... I'm going to end it for you... one way, or another."
- - Kirk, discussing his plan to end the war