Mutually Assured Destruction (MAD) was the doctrine that nuclear weapons, if deployed against another nuclear power, should be deployed en masse with the objective of completely destroying the other country's capacity to retaliate, and vice versa. In other words, if either the USA or the USSR ever used nuclear weapons against the other, it would be assured that neither the USA nor the USSR would exist anymore. Naturally this assumes both countries have a large enough stockpile to accomplish this - and they did.
The goal of a MAD strategy is counter-intuitive: it is not to win a nuclear war, but actually to prevent one. The theory goes that if each side knows that there is no way it can survive a nuclear war, it will get too scared to start one. Unless one or more of the superpowers decides on Taking You with Me or is ruled by an Omnicidal Maniac, the idea is that knowing that "the only winning move is not to play" will keep either side from escalating matters to the point that mutual destruction becomes inevitable.
Related to this is the Game of Chicken, also known as the hawk-dove game or snow-drift game. It is an influential model of conflict for two players in game theory. The principle of the game is that while each player prefers not to yield to the other, the worst possible outcome occurs when both players do not yield.
Needless to say, this theory made people on all sides of the Cold War very nervous. Indeed, before the end of the Cold War, most academics thought the acronym "MAD" was appropriate - the strategy seemed insane.* It may come up in hypothetical World War III scenarios or works set in the late-era (1980s) of the Cold War. With the fall of the Soviet Union, MAD has lost its value as the focus shifts to combating terrorists who do not have access to a large stockpile of nuclear weapons.
One of the theories for why the Cold War ended as peacefully as it did is that belief in this doctrine prevented the US and USSR from fighting any war directly against each other, for fear it would escalate to nuclear weapons and destroy both powers. Instead, it became a war of ideologies and economics, and according to the victors, the US eventually out-converted and out-spent the Soviets, who then collapsed under the weight of their own system.*
Where there is no parity between the two nuclear belligerents, The Moscow Criterion is used. This was developed by the British, who could not build and fire the same number of rockets as the Sovs and who did not trust the Americans to launch their own missiles to back up a MAD doctrine - instead, the aim is to have the ability to slaughter as many of the enemy civilians as possible, thus attaching a prohibitively high human cost to a nuclear release by the more heavily-armed power.
- Discussed in Silent War when The Sentry and Black Bolt face off. Given their respective power levels, and their unwillingness to surrender, the Sentry states that this would be the end result of their fighting at that stage. Black Bolt agrees, and leaves. The next time the Inhumans and the American government face off, Bob refuses to get involved.
- The backstory of Fallout: Equestria was that the megaspell was created and given to both sides to invoke this scenario and end the pony/zebra war. However, when the zebras believed they were doomed to lose the war anyway, they decided to go the "Taking You with Me" route and both sides ended up flinging them off.
- The truth is a little more complicated. Equestria's Minister of Peace created the megaspell as a part of the CARE initiative (Communually Assured Reciprocal Existence) with the intention of it being used to augment shields and healing magic. She gave the technology to both sides, hoping that if neither side would kill the other, both would give up on the war. It took both sides about four seconds to weaponize it instead.
- Played with on an intergalactic scale in Sonic X: Dark Chaos. Neither Maledict nor Allysion want the Eternal War to flare up again; when the Demon and Angel militaries collide, whole galaxies are exterminated and torn apart. But when the Metarex war distracts the Demons, Allysion realizes she can gain a massive advantage over her enemy by invading the Milky Way first. Her surprise attack quickly turns the entire Milky Way Galaxy into a hellish wasteland as the Demons and Angels go into open conflict.
- In MANE, an uneasy standoff had held between Equestria and the USR for a decade because both sides had enough nuclear weapons to destroy each other utterly. The title is also a pun on this trope: M.A.N.E stands for 'Mutually Assured Nuclear Extinction.'
- Visually deconstructed in WarGames. Joshua had just been programmed to play Tic-Tac-Toe against itself repeatedly until it "learned" that a win was impossible for either player. Joshua then played out every nuclear scenario it was loaded with, and determined that every single one resulted in mutual assured destruction, and thus was a "lose" for both sides, just like the Tic-Tac-Toe game.
- Dr. Strangelove is based around this, because the Russians have a doomsday device raring to go if they get hit with a nuke. One rogue general in the US air force sends nuclear bombers at Russia, because Ripper, like Turgidson, thinks it can be averted with a pre-emptive strike since the United States has a five-to-one missile superiority. The film notes that the reason this trope was not successfully invoked was because the Russians constructed their doomsday device before revealing its existence, thus negating any use it had as a deterrent in the meantime and instead guaranteeing their destruction if the Americans set it off out of ignorance (as General Ripper proceeded to do).
- In the middle of the film Ice Station Zebra, this Trope is discussed ("a wonderful acronym, if there ever was one!") as part of the rapid-fire Info Dump that explains why the film's MacGuffin (a surveillance satellite that went down near the titular polar station and which contains on film the precise locations of all the nuclear silos on Russia and North America) is so important: such information would surely allow the enemy to devise a "survivable" battle strategy for an all-out nuclear assault.
- This is how judgment day in...well, Terminator 2: Judgment Day occurs: when Skynet becomes self aware its creators panic and try to shut it down. Instead of launching everything at it's native United States, Skynet attacks Russia, with the nuclear retaliation resulting in that scene, the one scientists praised for how frightening and realistic it was.
- The Butter Battle Book features two cultures (the Zooks and the Yooks), seperated by a wall and, competing in an arms race to destroy the other side; however, each new Zook weapon (ranging from giant slingshots to bipedal mechs armed with chemical goo) turns back due to the Yooks developing the same weapon or a counter-weapon. Eventually, each side creates an apocalyptic bomb called the "Bitsy Big-Boy Boomeroo", and the story ends with with the generals of both sides on the wall poised to drop their bombs, waiting to see who will do it first.
- One such deterrent is devised in Harry Turtledove's Homeward Bound. Before that, this was far from the case, as the Race has better anti-missile technology than the major human powers and could be reasonably expected to intercept a large number of human nukes. Additionally, since the Race's larger Empire was unreachable, the destruction of their colonists on Earth would not cripple the Empire but would doom humanity. Throughout the Colonization books, Fleetlord Atvar is musing launching an all-out nuclear strike against all Tosevite territories in order to prevent them from spreading out into the galaxy, knowing that this would likely result in the planet becoming uninhabitable. One of the purposes of the Admiral Peary is to place a nuclear launch platform in orbit of Home, the Race's homeworld in Tau Ceti, a clear case of Gunboat Diplomacy: either the Race deals with humans on equal turms, or both Earth and large areas of Home will be destroyed. When the first ever FTL-capablestarship, the Commodore Perry, arrives to show that humans have the ultimate first-strike capability, the Race manages to device a MAD-like counter. Should humans launch a FTL strike against the three Race worlds, the Race will launch their STL starships on a collision course with Earth. An impact of even one ship traveling at 50% of the speed of light is likely to cause an extinction-level event.
- The titular One Man Armies of Mistborn: The Original Trilogy produce a similar effect: If one Great House sends its Mistborn to assassinate members of another House, the second House will send its Mistborn right back.
- The final campaigns of the Final War in the Bolo series amounted to this. The Melconians and the Concordat decided to Exterminatus every planet held by the other side at about the same time. Both sides succeeded. In the end, all that was left were scattered remnants of the surviving warfleets desperately searching for a planet that's still capable of supporting life so they can start over. As the scattered remnants of the Concordat were slightly larger, humanity technically won.
- The Salgari novel Le Meraviglie del Duemila is set on an Earth where every country has access to what basically amounted to nukes (it was written in 1907, so Salgari couldn't know about the concept), and, as it's a chemical explosive, every single country could potentially destroy the world, or at least wipe off the map their enemy. Quite sensibly, all countries went to the diplomatic table and resolved peacefully territorial and diplomatic disputes and other treaties to make sure nobody would go to war. And given everyone knows there is the will to use it on anyone who acts out too much, as it actually happens on page,note it works.
- This ultimately is what ends the forty-plus-year-long war between the Republic of Cinnabar and the Alliance of Free Stars in David Drake's RCN series: Both nations were on the verge of total economic collapse and continuing the war would likely take the rest of human space with them due to their importance in the galactic economy.
- Animorphs: Crayak and Ellimist, two Sufficiently Advanced Aliens who would likely destroy the entire universe and themselves along with it if they ever fought openly. This forces them to engage in Proxy Wars with such groups as the Yeerks and the Animorphs.
- A key part of The Cardinal of the Kremlin is a defense system that threatens to destabilize the world by ending this - if one side can shoot down the other's nukes, then the destruction is no longer mutually assured. The US ends up developing the ability to target incoming nukes, while the USSR develops a laser that could theoretically destroy a nuke if it hit one. They spend the entire book trying to steal each other's breakthrough on the system while trying to protect their own.
- In Doctor Who it initially looked like the Time War was a case, with both the Daleks and the Time Lords wiping each other out and the only survivors being the Doctor and the Daleks that keep popping up when they're supposed to be extinct. Then the Master turned out to be alive, and then the Time Lord Council came out of hiding, then it looked like the Doctor had pushed the button that almost wiped out both races, then it turned out the Doctor merely thought he had and actually hid Gallifrey in some kind of pocket dimension...
- One episode had Professor Duncan abuse Chang by using his restraining order to torment the guy. By the end of the episode, it is shown that Chang has gotten his own restraining order on Duncan, who then states the name of the trope.
- Star Trek: The Original Series
- One episode had two planets who tried to avoid MAD by simulating a nuclear war and having the people who died in the simulation shuffle into suicide booths, but leaving the infrastructure and environment intact. Which managed to keep the conflict going for over five centuries. Then the simulation had the Enterprise destroyed by a stray missile and Kirk quite vehemently refused to abide by their stupid rules. The leaders were certain that they would nuke each other to oblivion now that the rules were broken, but the Enterprise left before the conflict could be resolved fully.
- The Doomsday Machine was speculated to have been intended as the ultimate deterrent, "a weapon built primarily as a bluff. It's never meant to be used. So strong, it could destroy both sides in a war". But then someone actually used it. However, many Expanded Universe materials suggest that it was actually built as a weapon against the Borg.
- In Farscape: The Peacekeeper Wars John Crichton threatens to destroy the universe with the Wormhole Weapon both sides of the Peacekeeper/Scarran war have been chasing him for if they do not stop fighting this instant.
John: "Wormhole weapons do not make peace. Wormhole weapons...don't even make war. They make total destruction. Annihilation. Armageddon."
- In the The Greatest American Hero episode "Spoilsport," Bill Maxwell, FBI agent, tells Ralph about a last-ditch program: Spoilsport. In case of a nuclear war where the U.S. is losing, 10 nuclear missiles are held back and fired by computer the following day, so as the Soviets are digging themselves out of the rubble, the last of the missiles hit, given the U.S. the "win." The episode revolves around a General Ripper taking control of the missiles and launching one intended to start a nuclear exchange.
- The Tom Lehrer song "We Will All Go Together When We Go", from An Evening Wasted with Tom Lehrer, is a bleak look at the enormous scale of devastation a nuclear war would bring set to a jaunty tune.
Oh we will all char together when we char
And let there be no moaning of the bar
Just sing out a te deum
When you see that I.C.B.M.
And the party will be "come as you are!"
- Fishbone's "Party at Ground Zero", one of many, many, jaunty '80s tunes about nuclear war:
Party at ground zero
A "B" movie starring you
And the world will turn to flowing
Pink vapor stew
- Daniel Amos mentioned the possibility of nuclear armageddon in three separate songs on their 1984 album Vox Humana. "It's Sick" and "The Incredible Shrinking Man" just mention the bomb in passing, while "Dance Stop" is all about the masses dancing while the bombs fall.
Contortionists are caught up in the camera’s eye
The music explodes and the bodies fly
They're rating it a ten before they drop and die
“WELL IT HAD A GOOD BEAT!” was their very last cry
- Flanders and Swann used a calculation highlighting the insanity of M.A.D. - dividing the estimated destructive capability of the world's nuclear arsenals by the number of people then living - as the basis of their song, "Twenty Tons of T.N.T."
Ends the tale that has no sequel
Twenty tons of TNT.
Now in death are all men equal
Twenty tons of TNT.
Teach me how to love my neighbour,
Do to him as he to me;
Share the fruits of all our labour
Twenty tons of TNT.
- Invoked with the "Ruiner" table in Ruiner Pinball, as avoiding nuclear war is not an option.
- Twilight Struggle, being a game about the Cold War, uses the threat of this as a Nonstandard Game Over. If the DEFCON scale reaches 1, then the player responsible for playing the card that started the sequence loses immediately.
- The use of Exterminatus in Warhammer 40,000. Whatever threat was on the planet is probably dead, but now the Imperium is down a planet in a time where resources are scarce enough as it is.
- DEFCON is essentially a Mutually-Assured Destruction Simulator, directly inspired by the War Games example above.
- MAD: Global Thermonuclear Warfare, a little-known game by the Small Rockets (a now-defunct department of Criterion Games) that predates the above-mentioned DEFCON is Exactly What It Says on the Tin.
- Metal Gear Solid: Peace Walker discusses this and whether it works or not. Coldman intends to use the titular Peace Walker to prove that nuclear deterrence works (specifically that no man wants to go down in history as the great annihilator) by launching a fake nuclear strike, in the hopes that the receiving side will refuse to counterattack and destroy humanity. Turns out that a strong, charismatic leader in the wrong place at the wrong time can induce a "follow the crowd" effect, which causes cowards to become instant patriots who will sacrifice the world out of spite, and cannot be easily reversed by said leader changing his opinion. Whoops.
- The backstory of Wasteland has nuclear exchanges devastating the planet because of this trope.
- Wasteland 2 expands upon a group introduced in the previous game, the Servants of the Mushroom Cloud, by explaining that they believe in M.A.D. as a religious doctrine. They serve as the law enforcement of the "Canyon of Titan", holding the peace by threatening to detonate a live Titan II warhead if any raider groups attempt to take over. On a smaller scale, their "MAD Monks" offer protection to travelers through the canyon by threatening to detonate a dirty bomb (with a sizable radius) if confronted with aggressive raiders. A possible option in the game is disarming the monks' warhead; chaos erupts in the canyon if this is done, suggesting that the doctrine was keeping some semblance of order there.
- The Fallout series of games (which are spiritual successors of the above-mentioned Wasteland games) are based in the post-apocalyptic world created by the mutual destruction of a nuclear war between China and the United States.
- Various Civilization games invoke this. Using one nuclear weapon in Civilization will get those who are not at war with you to declare war. Earlier games would also take the AI's nuclear arsenal vs. the players into account when making one sided deals. Civ 6 ramped it up by making Nukes a bit more life like by making radiation last for decades of in game time and lethal to any units in the area (previous games had radiation represented by pollution which would destroy only productivity of the affected tile until a worker could clear it and rebuild the damaged improvement). The mechanics also allowed the attacked player to keep his entire arsenal in play, provided he built a Nuclear Trifecta, thus allowing him to attack the player who used weapons on him some time later. Between the universal lethality and the destruction, both empires would be quickly reduced in capacity in the end game.
- In Disgaea 5: Alliance of Vengeance, this is used as a threat in Chapter 11: Celestia has a Weapon of Mass Destruction, Armageddon, that can obliterate a large chunk of the Netherworlds and has a high chance of killing Void Dark. Christo, not wanting his newfound demonic allies to be compromised or for there to be destruction and death on such a huge scale, threatens to tell Void Dark where Celestia is and thus enable an equally destructive counterattack if the weapon is fired. This gets the higher-ups of Celestia to back off.
- In Prismata, the war between humans and AI eventually reaches a cease-fire because of this.
- Schlock Mercenary: Discussed. When the galaxy was bound by a Portal Network, there was no Mutually Assured Destruction; the wormgates limited the size of ships that could use them, meaning that it was far easier to defend a system than attack. With the invention of the teraport, that limit was removed, edging the galaxy closer to MAD—but the use of Teraport Area Denial prevented the most dangerous uses of the technology. Then "long-guns" were invented, giant cannons that shoot through hyperspace and overwhelm TAD; with proper location data, they can shoot at anywhere in the galaxy from anywhere in the galaxy. The galaxy was well and truly back in a state of MAD, since there was no defense. The various galactic leaders insist that while this system is terrifying, that's why it works; no one likes the fail state. Petey points out that eventually they'll find someone who does like the fail state, and then the entire galaxy will die, so they need to find a better solution. Finally, there have been multiple previous epochs of galactic history that were destroyed by failed MAD policies. The very rare surviving species call the long-guns "end-guns" for this reason.
- In the French sci-fi series Once Upon a Time... Space, an episode detailing Earth's history between The '80s (when the series was made) and the thirty-first century (the setting) had the two major powers locked in cold war and a series of small-scale proxy conflicts due the fear of mutual destruction. Then the respective dictators decided to distract their oppressed people by starting a war, and launched the missiles at the same time. The scene is represented with the dictators pressing the launch button of the missiles and then blowing up at the same time, with the narration continuing with "In the year 2200, Earth-- or rather what remained of it..." to drive home the point (it was for kids, so they wanted to make sure they got it).