A Nuclear Error

During the Cold War (and even since), fiction has made some inaccurate assumptions about nuclear weapons and nuclear weapons policy. Also, it made for more exciting drama when writers could pretend that it was easy for some American or Soviet General Ripper type to get control of his country's nukes. However, as the comments below indicate, actual policies changed quite a bit during the Cold War depending on which side one is talking about, so there can be a lot of factual leeway in such situations, especially since many of the facts below have come out only since the 1990s.

Types:
 * Counter-city policies (Fail Safe): When early basic plans involved "throw everything we've got at the commies", later American nuclear policy during the Cold War was to focus on military targets. Population centers like Moscow still would have been bombed, true, but only as leadership targets (and probably with smaller warheads). Industrial targets in cities were last-resort targets. The Soviets did target civilian populations, but not to a massive extent while it was in fact the British who carried over WWII Bomber Command doctrine of area bombing cities due to the smaller number of warheads in stock.
 * A Soviet first strike (Threads): the Soviet Union had a "No First Use" policy (= only use nuclear weapons if first attacked with nuclear weapons) in the 1980s. Before then, there were plans for first use, but only in response to an imminent Western attack. War Games is correct in its usage, as there never was an actual first launch (it was all the military's computer playing a game of Global Thermonuclear War, with the first strike being made by a teenage hacker, unaware he's actually making the US think they're under attack).
 * During the Cold War and post-Cold War analysis of East German, Czech and Polish documents, many people confused the term "pre-emption" with "first strike". Pre-emption is like this: it is considered self-defense to draw and shoot if the other guy starts to draw his gun first.
 * The rogue launch:
 * In general, Soviet Cold War weapons had coded locks, requiring authorisation from the top commanders to be armed. During the Cuban missile crisis however, there were missile carriers capable of independent launch of armed missiles.
 * On the US side, until the 1990s, it would have required at least three people to launch an armed attack from a submarine (and a missile launch from a submarine would be damned near impossible without the full support of the crew). Other launch methods had the coded locks. This system, however, only really existed after 1962.
 * Confirmed. Recently declassified data has revealed that the US protections vs. "rogue launch" pretty much only existed from 1961 onwards. In the 50s, there were no physical safety interlocks on US nuclear warheads, at least a half-dozen senior officers had the authority to launch a nuclear strike on their own initiative (said authority intended to be used only if a war situation occurred and the President was out of communication, but as with the Trident submarine example below the only real enforcement was the honor system), and in some cases, bomber units were under orders to attack Russia immediately if they ever stopped receiving periodic "don't attack" messages from HQ — i.e., the same situation as the fictional 'Fail-Safe' example.
 * Purportedly, another current-era precaution vs. 'rogue launch' is that ICBMs are not targeted using conventional latitude-longitude but instead use an entirely arbitrary coordinate system created specifically for the job. And the missile launch crews do not have a copy of the map and only input arbitrary strings of #'s that are given to them by higher authority. In short, even if you could figure out a way to arm and launch your nuke, you still can't aim it without somehow obtaining access to information well above your pay grade. As a further precaution, the 'default' target for most ICBMs is 'the middle of the ocean' and the actual target coordinates are only provided at the same time a valid launch order is.
 * In the UK, on the other hand, until 1998 the RAF's nuclear missiles were secured with nothing more than a cylindrical bicycle lock key. Royal Navy Trident submarines are still able to launch without a code since a mere ten minute warning meant that if a nuclear war had broken out, it is unlikely that there would be time to issue relevant orders to their submarine captains. Plus, no officer of the Royal Navy would ever consider acting without orders or the proper cirumstances. It just wouldn't be cricket.
 * France faced the same issues, yet they figured they weren't worth the potential risks of starting World War III. They installed the same kind of locks the US and USSR used. They are also less fond of cricket.
 * The nuclear button (Eagle Strike): Neither side in the Cold War had nor has a nuclear launch button, even in their "nuclear footballs". The nuclear footballs contain information about nuclear stategy, and equipment for the leader to communicate with, and authenticate himself to, the military personnel in individual silos (etc) who would actually carry out a launch.
 * Presidential power: The US President cannot launch a nuclear first strike without the cooperation of the Secretary of Defense or any other administrative official that's been appointed/approved by Congress (e.g., CIA director, most of the Presidential Cabinet...). Ordering a retaliatory strike was something a number of people had authority to do. The plane known as "Looking Glass" had authority to do so in the event that the National Command Authority was killed or out of contact. Were DEFCON to reach level 2, both pilot and co-pilot would be required to wear eye-patches in case a nuclear explosion render their exposed eye either momentarily or permanently blind, but nowadays they use goggles. While current policies are classified, it can be assumed that after a major strike on the USA, remaining weapons would be released, with or without higher command. For the Soviets, supposedly, the semi-automatic Perimetr system had three human operators who were able to give the order to launch all remaining warheads in case when on-site seismic detectors detected multiple nuclear explosions on Russian soil and high command is inaccessible. It is unknown if the system is still in use today.
 * Using a missile warhead as a stand-still bomb: Since the Cuban Missile Crisis, virtually all nuclear warheads are designed so that they will only go off after being exposed to certain environmental conditions- as in the large numbers of Gs associated with a missile launch.
 * Most films behave as if only the USA and USSR had nukes. In reality, the UK, France, China were also nuclear powers before the nuclear non-proliferation treaty. Later, India and South Africa produced weapons before the end of the Cold War. In an open secret, Israel is widely believed to possess nuclear weapons since the 60's or 70's. Several European countries had American bombs stationed there too. South Africa disarmed in 1990; Pakistan joined the club in 1998. North Korea has a limited number of very primitive nuclear weapons, lower grade than those used in World War II, but lacks anything to deploy them with, technology it eagerly seeks to develop. Iran had a nuclear program but officially (with little doubt that it continues unofficially) suspended it as part of a deal with the United States. Syria was also suspected by some of having nuclear weapons programmes, though the long ongoing Syrian civil war leaves the state and future of these programs to more speculation. Many European countries still have American nuclear gravity bombs stationed there - the Netherlands, Germany and Turkey among others. Their pilots train to use them; in the event of war, the US bombs would be turned over to local NATO forces.
 * In fact, it's widely suspected that the Vela Incident was a joint Israeli/South African nuclear test, as S. Africa was being subjected to multiple embargoes and sanctions due to Apartheid, and Israel was looking for a nation to help them gain nuclear capability because they were being embargoed by some nations in the West.
 * Disarming a ICBM Post-Launch: Deployed strategic ballistic missiles do not have any mechanisms for the attacker to remotely disarm or destroy the weapons after launch. For all intents and purposes once the missile has been fired it can only be stopped either by mechanical malfunction or interception. Missiles which are used for testing are modified with a self-destruct mechanism in case something goes wrong, but live warheads are not used for testing the missiles.

See You Fail Nuclear Physics Forever for errors involving nuclear technology.

Anime and Manga

 * In Future War 198X, the inventor of America's new Missile Defense System is kidnapped by Soviet spies. When the Americans realize that he is being taken back to Russia by submarine, they figure that it would be better to kill their greatest inventor than to let his creations fall into enemy hands. They send out a sea-based nuclear warhead to destroy the boat, thinking that it will be a small enough accident that it can be blamed on an accident aboard. The result is far more enormous than anticipated, setting off the entire horrific war the rest of the movie narrates.

Comics

 * The Metal Men commits a similar mistake to that described for The Green Hornet under "Live-Action TV." Magnus's bomb group is about to let go and obliterate his evil robot twin, but when he sees the Metal Man "Plutonium" he orders them to hold fire for fear of setting it off. Evil!Magnus knows this and lampshades it to Platinum seconds before Real!Magnus perceives the situation. Of course in this case it might not be an error because Plutonium was a sentient creature which could choose its moment to explode.

Film
"Jordan Tate: If the sub blows, won't the nukes go? Casey Ryback: No. They won't detonate. Just sink with the sub."
 * Doctor Strangelove, or How I Learned to Stop Worrying and Love the Bomb may be the epitome of this trope. General Jack Ripper issues an order for his bomb wing to attack their targets inside the Soviet Union. The Soviet Union had developed a device that would immediately trigger a nuclear holocaust in the event of an attack on Soviet soil. Nobody but Ripper could order his wing to return, and the Soviet device would go off it any attempt was made to disable it.
 * In addition, when the "Leper Colony" is damaged by a Soviet missile, they are leaking fuel and the radio is destroyed. As a result the crew is unable to reach the bomber's designated targets or contact base for new orders. Rather than ditch the plane, the pilot elects to bomb the nearest Soviet installation.
 * Of course, it is a gung-ho cowboy pilot who just thinks his country entered a nuclear war and has little hope of survival himself, and might return to find all his family and friends dead. His motivation to follow policy to the letter might be slightly compromised.
 * According to a featurette on the DVD, the reason Kubrick decided to make it a comedy (the novel it was based on had a serious tone) was because he did enough research to learn the central premise was impossible, but figured people wouldn't criticize its accuracy if it didn't take itself seriously to begin with.
 * Fail Safe - A bomber group is launched with nuclear weapons and receives the 'go-ahead' signal because of a technical failure. Because they are literally following their instructions, which tell them to ignore stand-down orders, the U.S. has to give the Soviets whatever information they can to tell them how to shoot down their own planes but one bomber escapes the defences and heads for Moscow. When the inevitable becomes clear, the President offers a solution to his Soviet counterpart to avoid a nuclear holocaust. Since their largest city is doomed, he will offer up America's largest city in return as an Heroic Sacrifice to save the world. When the bomb goes off over New York City, the pilot who had to drop it commits suicide.
 * The president's family was also in New York City.
 * Interestingly, it is suggested by a prophetic dream that General Black was expecting to die or be demoted for failing his duty.
 * In the novel, it's made clear that the dream is Black's conscience torturing him about what he knows his job is to do. He knows that to make it stop, he just has to leave Strategic Air Command - but to do that would be to give up all he's ever lived for.
 * The Bedford Incident. A gung-ho destroyer commander harasses a Soviet sub with the intention of forcing it to the surface. Unfortunately he also rides his crew equally hard, so a keyed-up officer launches an anti-sub missile when he hears the words "Fire One" (the captain was actually saying "If he (the sub) fires one, then I'll fire one"). The by-now equally keyed-up Soviet submariners respond with an atomic torpedo before they're destroyed.
 * The captain had gone so far as to tell the ensign he'd been riding through the whole movie not to fire unless he said "fire one" twice...and then went and said it twice in the above quoted sentence.
 * Note though that tactical nuclear weapons, like atomic torpedoes, tend to lack the technological protections and locks that are used on strategic nuclear weapons, like nuclear missiles.
 * Averted in (of all places) a Steven Seagal movie, Under Siege. U.S.S. Missouri's big guns are about to fire at a submarine carrying stolen nuclear-tipped cruise missiles.


 * Superman (1978). The United States would never test launch missiles with nuclear warheads (armed or not), for exactly the reason shown in the film: any accident could cause vast destruction. Dummy warheads are always used. Even worse, a newspaper headline before the test mentions that live warheads would be used. So the U.S. military said publicly that they were going to pull this harebrained stunt, which violated the 1963 Limited Test Ban Treaty, and no one objected.
 * They did, actually, with the nukes set to detonate at apogee. Obviously in the atolls, not in reach of CONUS. That's how the EMP phenomenon was discovered. These tests occurred before the 1963 treaty.
 * The Last War averts several tropes by making the sides the Federation and Alliance, and not pointing fingers at any countries in the nuclear attack at the end.

Literature

 * Averted in The Hunt for Red October (though not in the movie for reasons of drama). First it's pointed out that Ramius could have launched his missiles virtually from harbour if he wanted to start World War III, and that several officers are needed to launch the missiles, more even than a US submarine. A Politburo discussion about options for preventing the defection of Ramius, specifically pointed out that without the appropriate signal from an accelerometer, the weapon couldn't detonate. Though the film version does have The Mole attempting to sink the October by way of detonating one of the missiles aboard. It's specifically pointed out that the missiles can't be launched, but the fuel and non-nuclear explosives on just one is more than enough to incinerate the ship.
 * Also, the missile the The Mole is attempting to blow in place had been specifically rigged beforehand with a non-standard detonator package, precisely to enable this contingency plan.
 * While not quite an Accident, but insanity, in the last book of the Genesis of Shannara trilogy, the last man living in a nuclear launch facility is finally driven to the point where he launches the remaining weapons in his base's arsenal. The two key console had been changed to a single man with a code, and all weapons pre-targeted.
 * Of course this was already After the End, with "The Great Wars" having already destroyed the majority of civilization (in fact it was during these wars that the normal safe guards were removed that allowed one person to launch the entire U.S. ICBM stockpile, that's how bad they got), so instead of starting a war like most of the other examples did/almost did this one just finished up the destruction, basically causing so much cataclysmic damage it set a reset switch, allowing the survivors (who were magically shielded), to start over from scratch.
 * A scary, scary SF short story that this troper cannot remember (but see the compilation "Destination Universe!") describes a robotic nuclear weapon landed on Earth from a long-ago war which is fired on by humans. It explodes, thrusting the Earth into the Sun, because it doesn't know it's not the same war and would have had no choice even if it had.
 * In Animorphs #46: The Deception, the villainous admiral's Batman Gambit involves faking a nuclear attack by the Chinese on a United States aircraft carrier, giving him an excuse to have a submarine under his command "retaliate," which would actually involve the Chinese and kickstart World War III. The goal is to weaken the entire world enough for the Yeerks to switch from infiltration to open invasion of Earth.
 * It is claimed that Tom Clancy revealed the details of the "Looking Glass" policy in his novel The Sum of All Fears, but for obvious reasons this has never been officially confirmed (or denied).

Live-Action TV

 * The short-lived comedy series Woops! begins on the notion that a couple of kids with a radio-controlled airplane accidentally interfered with US missile control systems, causing global thermonuclear holocaust. Of course, the entire show is built in this sort of hyperbolic farce.
 * Not quite as farfetched as you might think, actually.
 * In the British comedy series Whoops Apocalypse a series of Pythonesque misadventures leads to an accidental rocket crash being interpreted as a preemptive American strike on Moscow.
 * The film of the same name has the same writers but an almost completely different plot, in which a submarine commander accidentally orders a nuclear strike because a stage hypnotist has implanted the command to say "Fire!" whenever someone snaps their fingers.
 * The Green Hornet episode "Invasion from Outer Space". An unarmed H bomb (without an installed detonator) inside a truck can supposedly be set off by a detonator attached to the outside of the truck. This is physically impossible.

Music

 * "99 Luftballons". The titular balloons show up as unidentified blips on a radar screen, so one side sends fighter jets to investigate. The other side takes this as an attack and retaliates with the nukes.

Real Life

 * So far as anyone knows, there has never been in accidental nuclear detonation. But there have serious errors, usually resulting from midair collisions, where nuclear weapons have been lost temporarily. Others have occurred where the non-nuclear components of the bomb detonated due to accidents...but as they must detonate in a precise sequence with extremely tight time tolerances, the only result was spreading radioactive material around.