->''"We have to face the facts. The technology exists. It can't be uninvented. Once it gets out there, it will be abused. None of us can prevent that from happening. But we can choose, where we want to be and on what side when the end finally does arrive. Do you want to be the destroyed? Or the destroyers?"''
-->-- '''Boyd Langton''', ''{{Series/Dollhouse}}''

Consider the following:

* Major premise: [[WhenAllYouHaveIsAHammer All weapons are made to be used.]]
* Minor premise: [[HumansAreBastards All humans are prone to using weapons.]]
* Conclusion: [[InYourNatureToDestroyYourselves All weapons will be used.]]
* Consequent: [[MightMakesRight I'd better]] [[SelfFulfillingProphecy do it first.]]

A subtrope of IDidWhatIHadToDo, this is a stock explanation for those operating on the extremely cynical end of the SlidingScaleOfIdealismVersusCynicism. When such characters have to employ a morally dubious weapon but [[PretextForWar still care about justifying it]], this will almost always be the go-to rationalization. The argument goes that once a weapon has been invented it will inevitably proliferate and be used, and therefore the only sane response is to use it as early and often as possible. Expect to hear it as a paper-thin excuse from GeneralRipper, the WellIntentionedExtremist, or TheSocialDarwinist as they sprint gleefully towards the MoralEventHorizon with the rest of the world in tow. If your ''heroes'' are using this justification, you probably live in a CrapsackWorld, a world of BlackAndGrayMorality at the least or ProtagonistCenteredMorality at the worst.

The title is, of course, a common subversion of TheGoldenRule.

* Kanako from ''Anime/StarDriver'' uses this as her justification for working with Crux and fighting Takuto.
* The warring sides of ''Anime/MobileSuitGundamSEED'' use this trope as justification for their deeds; both are led by extremists who aim for nothing less than the complete annihilation of the other side down to the last man, woman and child. Therefore, backing down and depending on MutuallyAssuredDestruction is equivalent to surrender. Things escalate when both sides acquire N-Jammer Canceller technology and a battle ensues where the Federation launches dozens of nukes at ZAFT's civilian population while ZAFT have a nuclear-powered WaveMotionGun pointed at Earth; had [[spoiler: The Three Ships Alliance]] failed to destroy these [=WMDs=], the result would've been a MutualKill. Fortunately, the extremists are killed during the battle, after which both sides have a HeelRealization and ''[[WarIsHell finally]]'' begin negotiations.
** One has to consider the additional fact that both the Federation and ZAFT were being manipulated by [[spoiler:Rau Le Creuset]] who believed the war can only be stopped for good by [[OmnicidalManiac having the two mutually annihilate each other, thus rendering humanity extinct]] and unable to war among themselves just for the sake of being different from each other. In other words, the spoiler character was invoking this trope.

* In the ''ComicBook/XMen'' comics, one of ComicBook/{{Magneto}}'s main rationales in his [[SuperSupremacist war on humanity]] is an assumption that humans will inevitably enslave/exterminate/oppress mutants unless mutants do the same to them first (or at least separate themselves from humans). It's one of the main sticking points in his philosophical differences with [[TheIdealist the more idealistic]] Professor Xavier.
* ''Comicbook/{{Hellblazer}}'': When John Constantine was hired by a corrupt adviser to the Royal Family to discreetly resolve some demon business, his anarchist friend tried to warn him that they'll betray him [[YouHaveOutlivedYourUsefulness as soon as his work is done.]] John is not unaware of the possibility, and reassures his friend that he will follow his usual strategy: "Screw them before they screw me."

* Quoted almost verbatim by Leaf in ''FanFic/PokemonClefairyTales'' one time she commanded her Rattata to use Quick Attack.
-->'''Leaf''': Do unto the other guy before he does unto you!

* The infamous GeneralRipper from ''Film/DrStrangelove'' gives this excuse, claiming he's giving the US "the best kind of head start."
* The explanation for the construction and deployment of DESTINI in ''Film/TheCore'': "''Someone'' was going to build it, so we built it first."
* Said word for word in ''Film/VanHelsing'', with Dracula starting and Igor finishing the quote. However, they were talking about generally being horrible to people rather than a particular plan or pre-emptive strike.
* According to ''Film/TheMenWhoStareAtGoats'', both sides of the Cold War ended up doing psychic research because, even though not many people on either side actually ''believed'' there was anything in it, they couldn't let the other side lead the field ''just in case'' it turned out to be real.
* In the BadFuture the protagonist of ''Film/{{Paycheck}}'' is trying to prevent, a machine capable of seeing into the future predicts a nuclear war. [[SelfFulfillingProphecy So the US decides to strike first,]] [[GenreBlind starting said war]].
* In ''Film/TheDarkKnight'', the Joker attempts to set up this kind of scenario with two barges, one filled with ordinary civilians and the other with criminals. They are each given a detonator and the same instructions: Blow up the other boat before they blow up you, and if neither boat blows up within a certain time limit, then he'll blow them ''both'' up himself. [[RousseauWasRight Neither group plays along with the Joker's game]].
* Magneto's motive in some ''[[Film/XMenFilmSeries X-Men]]'' movies. In ''Film/X2XMenUnited'' and ''Film/XMenFirstClass'' it's quite clearly "do unto them ''what they just tried to do to us'', so they don't get another shot at it". In ''X2'' this involves a weaponized version of Cerebro; in ''First Class'' it involves a ton of missiles fired by US and Soviet fleets.
* In the 1950s ''Film/StTrinians'' movies, the school song contains the lines:
--> Let our motto be broadcast, "Get your blow in first"\\
She who draws her sword last always comes off worst!
* The Pluckans [[EarthShatteringKaboom trancklucate their unnamed sister planet]] in ''Film/KinDzaDza'' "so that they don't do that to us". [[ThoseTwoGuys Wef and Bi]], who are from that exact planet, seem to be fine with that, because their people ''[[TheExtremistWasRight did]]'' plan to do the same for the sole reason of "because fuck you", and they are being good sports to the winners:
-->'''Gedevan''': Why did they do it?\\
'''Wef''': So that we don't do it to them first.\\
'''Gedevan''': And why would you do that?\\
'''Wef''': So that they don't hang over our heads.
* ''Film/StarshipTroopers'': Both sides see the other as a hideous horde of insane vermin, who hate everything their very genes stand for (humans represent arrogance and infighting, bugs represent obedience and gluttony) and [[GuiltFreeExterminationWar will do anything they can to wipe the other side out]]. Fancy that.

* In ''Literature/DragonBones'', Ward comforts himself with this after killing a mere boy, telling himself that the boy was a bandit who would have killed him without a second thought if he had had the chance.
* This trope is the very basis of ''Literature/EndersGame'' by Creator/OrsonScottCard. Instead of preparing for another alien invasion, mankind chooses to attack first this time.
* Subverted in the ''Literature/HIVESeries''. The big Council 'O Evil's policy is "Do unto others." Yeah, that's the entire motto.
* In Creator/LarryNiven's ''Literature/KnownSpace'' stories, the ARM ("Amalgamated Regional Militia," the police force of the United Nations) exists primarily to stop this sort of thing from happening.
* Occurs in the Creator/RobertAHeinlein short story "Solution Unsatisfactory". One of the U.S. characters considers having everyone who knows about the secret of the radioactive dust shot, but decides that the enemies of the U.S. would eventually discover it and use it against the U.S. anyway. The U.S. goes ahead with creating and using the dust itself.
* In Alexander Zorich's ''Tomorrow War'', this trope is a bitter discovery for heroes. They believed they were defending Earth against an unprovoked Concordian invasion, but it turns out [[spoiler:the Earth prepared invasion as well, and Concordians only ''managed to'' fire first, 'cause they were better prepared]].
* In the novel ''Literature/TheKillingStar'' by Charles Pellegrino and George Zebrowski, the aliens use this as a motive to wipe out humanity.
* The third, unnamed Entian power in Creator/StanislawLem's ''Literature/ObservationOnTheSpot'' was attacked by ''both'' [[EnemyMine Lusanians and Kurdlandians]] for the fear of them getting hit by the DepopulationBomb they've got rumors of (or were developing themselves, it's somewhat unclear). Poor southerners never stood a chance, though the reader is left with the impression that they ''indeed'' planned [[NotSoDifferent to do the same]] to their northern counterparts. Interestingly, even the fact that the third power ''existed'' is suppressed in both countries.

[[folder:Live-Action TV]]
* ''Series/{{Dollhouse}}'': Used when Rossum's founder makes a last ditch effort to convince his "family" that he needs to [[MassHypnosis mind control the world]]. Adelle [=DeWitt=], not above morally dubious actions herself, calls him "[[YoureInsane spectacularly insane]]".
* In ''Series/{{Firefly}}'', one of Jayne's lines includes the phrase "I'll kill a man in a fair fight...or if I think he's going to ''start'' a fair fight," though he then goes on to list a few other possible reasons.
* Max on ''Series/LivingSingle''.
--> "It's not revenge; it's prevenge. Getting to them before they get to you."
* This was Season 3 of ''Series/StarTrekEnterprise'' in a nutshell, until the humans found out both sides were being played by the [[LetsYouAndHimFight Sphere-Builders.]]
* An episode of ''{{Series/Bonanza}}'' had a family of squatters led by a matriarch who claimed no one would give them a fair deal, saying there were two laws, one to protect everyone else and their law which was essentially "An Eye For An Eye." Their conflict with the Cartwrights starts when one of the boys kills one of her sons in self defense after he tried to shoot him in the back, ''twice'', when the Cartwright tried to stop him from setting a clearing fire that would have burned an entire populated valley. Despite their stance of avenging slights the family acts in a way that actually causes confrontations, like squatting on other's land and breaking out rifles every time they meet someone. The matriarch's attitude has caused her sons to act violently when opposed and made it a SelfFulfillingProphecy, though most of her children don't agree with her position. In the end, [[spoiler: her surviving children refuse to go to war with the Cartwrights and she decides to make peace with the family, ending the feud on a positive note as she accepts Ben's offer to help her family settle in a new home]].
* In episode 7 of ''{{Series/Survivor}}'': Blood vs. Water, [[spoiler: Tina reveals to Monica that Kat wants Monica to be voted out, which would clearly break the Galang women's alliance. Monica has a grim realization:]]
--> [[spoiler: '''Monica''': I teach my kids "[[TheGoldenRule do unto others as you would want them to do unto you]]"... but you know what? In ''{{Series/Survivor}}'', I figured it out: it's "do unto others ''before'' they do unto you".]]
* In Series/HillStreetBlues, Sgt. Yablonsky would dismiss the police day watch with the above phrase almost exactly. "Let's do it to them before they do it to us." If it wasn't for Captain Furillo riding herd on Lt. Hunter and keeping his "destroy the village to save the village" tendencies in check, the entire police force would have become what Joyce Davenport sardonically referred to the police as: a Nazi occupation force.
** Apparently the showrunners realised the UnfortunateImplications, because Yablonski eventually got some dialogue making it clear that he didn't mean his catchphrase so literally as to justify PoliceBrutality.
* PlayedForLaughs on ''Series/TheRedGreenShow'' when Mike Hamar (a career criminal) tries to pass this off as a biblical quote.
--> '''Red:''' I don't remember that in the King James Version. Maybe the ''Jesse'' James Version.

* In ''VideoGame/TheElderScrollsIIIMorrowind'', the ThievesGuild in general and especially Master Thief Gentleman Jim Stacey are normally violence averse. Despite their best efforts to bribe and/or blackmail their rivals in the [[TheSyndicate Camonna Tong]], they are [[MurderIsTheBestSolution forced to kill]] members of other factions that are planning to kill Stacey or other members of the Guild.

* The ''VisualNovel/ZeroEscape'' series revolves around several DeadlyGame[=s=]. Naturally, even heroic participants are worried by the fact that their 'opponents' could easily betray them if left alive. Given that several murderers are also participating, there are actually times when killing someone ''is'' the right and sensible decision. Not shooting [[spoiler:Eric]] in ''[=ZTD=]'', for example, will lead to a bad ending where he fatally shoots the protagonist.

[[folder:Western Animation]]
* ''WesternAnimation/RickAndMorty'': in "A Rickle In Time", Rick and his grand-kids are split into two timelines. He attempts to fix the issue by merging their timelines back together, but runs into a snag, and immediately assumes that this means the other Rick gave up on merging and have moved on to trying to kill the other, motivating both to kill the other before they are killed.

[[folder:{{Real Life}}]]
* This line of thinking underpinned much of the nuclear proliferation in the Cold War. While nuclear weapons (utilising nuclear fission) were still weak, to the point that it would take half a dozen of the USA's stock of just 500 to completely destroy cities such as Shanghai or Warsaw outright (though the firestorms generated would have been largely sufficient even in the event of a single strike), certain US generals such as [=MacArthur=] talked openly about nuking the Commies into submission. Of course, the Soviet Union's invention and mass-production of the thousand-fold more powerful nuclear fusion ('hydrogen') devices and [=ICBMs=] in the early 1960s changed all that.
** First two and only uses of Nuclear Bombs in warfare were deployed because of this trope. The United States knew that Japan would fight to the last man, woman, and child to defend the home islands and did not like the prospect of invasion that would have to be done to win the war. Casualties were expected to be some of the costliest in American History. (Fun Fact: About Half a million Purple Hearts, an award given to US military personnel for injuries sustained from enemy combat, were ordered in anticipation. As one historian put it, they were the best war surplus. The United States would not need to place another order for the decoration until 2000! Even then, the original WWII era medals are still given out... the country is just getting close to running out of them half a century later.). Needless to say, Truman recognized that there would be a lot of American troops killing Japanese civilians and vice versa and he had an advantage that could kill more of them before they killed his own.
** The entire reason the Soviet Union even sought a Nuclear Bomb was because the only people who had one at that time were people who were aggressively opposed to their political style. It didn't help that America had used Nukes in the past, and did threaten a first strike whereas the Soviet Union maintained Second-Strike Only policies (and meant them, not that the Americans knew that at the time).
* A serious debate in the Soviet 1970s was whether or not it was best to nuke the PRC's atomic and rocket research facilities, since many argued that an escalation of the Sino-Soviet border skirmishes into a Total War was basically inevitable: the Chinese were crazy, they said (with some justification, as the Cultural Revolution was ongoing), and would never again accept 'peaceful co-existence' because it constituted acceptance of the heretical doctrine of 'Soviet Revisionism' (i.e. administration of the country by bureaucrats and not 'the people' themselves) and thus an end to Mao's much-vaunted 'Perpetual Revolution'. Therefore, the Chinese had to be nuked and they had to be nuked ''now'' before they got their hands on nukes capable of reaching the European republics of the USSR. Initially, cooler heads prevailed as it was hard to counter the incredibly obvious point that [[SelfFulfillingProphecy the quickest way to start a Total War with China was by nuking them]]. But as the Cultural Revolution, the Chinese nuclear program, and the border skirmishes all escalated the Soviets eventually agreed that they really were on a course to Total War and something had to be done. Accordingly, they merely threatened to nuke the PRC's research facilities if they refused to negotiate an end to the border skirmishes (while accepting the Chinese development of nuclear weapons in principle). Which they did, ushering in Sino-Soviet Détente.
* It was [[UsefulNotes/AdolfHitler Hitler's]] favourite excuse for invading countries. Soviet Union also loved using this excuse. Some ''Wehrmacht'' fanboys and German nationalists ''still, to this day,'' follow the official line of Nazi Germany: that the Jewish puppetmasters controlling the Soviet Union were going to make it invade Germany and then exterminate all European people (because the superior intellect and morality inherent to European races made them the only ones capable of resisting Jewish manipulation). DoUntoOthersBeforeTheyDoUntoUs [[GuiltFreeExterminationWar was invoked to morally justify]] the war.
** "Anyone who has ever looked into the face of a Red commissar knows what the Bolsheviks are. There is no need here for theoretical reflections. It would be an insult to animals if one were to call the features of these, largely Jewish, tormentors of people beasts. They are the embodiment of the infernal, of the personified insane hatred of everything that is noble in humanity. In the shape of these commissars we witness the revolt of the subhuman against noble blood. The masses whom they are driving to their deaths with every means of icy terror and lunatic incitement would have brought about an end of all meaningful life, had the incursion not been prevented at the last moment" - German Army Information Pamphlet
** "The battle against these subhumans, who've been whipped into a frenzy by the Jews, was not only necessary but came in the nick of time. Our Führer has saved Europe from certain chaos." - German Army gunner Karl Fuchs, letter written 4th August 1941 (translated by Horst Fuchs Richardson)
** "What the Asiatic hordes would not have wrecked, would have been annihilated by Jewish hatred and revenge." - German Army Captain E.P., letter written 15th February 1943 (translated by Stephen G. Fritz)
** Interestingly, although German propaganda was fairly clear on the point that Judeo-Bolshevik overlordship would be replaced by German rule, no mention was made of the German authorities' genocidal plans for the region's non-Jewish population. [[note]] This is because the basic idea seems to have been to exterminate a quarter of the region's population (c. 30 million) in the short-term and enslave the rest, who would be sterilized and exterminated as needed to make room for settlement by ethnic Germans in the medium-term - the long-term goal of course being to replace the entire population with Aryan-German settlers (though some Fit elements of the more Aryan native ethnicities might not have been sterilized or exterminated) [[/note]] This allowed German military personnel to feel not just that they were waging a defensive war of liberation, but [[{{Irony}} that they were fighting to stop genocide]]:
** "Now I know first hand what war really means. I also know however that we are forced into this struggle against the Soviet Union. For God have mercy on us, for if we had waited, or if these beasts had come to us. For them the most gruesome death is too beautiful. I am fortunate, therefore, that I should be here to put a stop to the handiwork of this genocidal system [völkervernichtenden]" -- German Army private Frederich Fallnbigl, letter written July 1941 [[note]] printed in David Redles' ''Hitler's Millennial Reich: Apocalyptic Belief and the Search for Salvation'' p.175 [[/note]]
* Another interesting point relating to the Conspiracy Theory that papa Stalin was about to invade Germany: when UsefulNotes/TheHolocaust became popular knowledge in the 1960s some of those groups switched to a "Stalin-Bolshevik" model. The last popular scholar to advance the view that the Soviet Union was about to attack Germany was the Soviet defector Victor Suvorov, who in the 1970s used circumstantial evidence hinting at Soviet plans to counter-attack the Germans on the borders of the Soviet Union and drive them back into Germany when the war began as 'proof' that the Soviet Union was going to declare war on Germany. Direct examination of the actual plans in the 1990s revealed the true nature of the planned operation, a defensive counter-offensive. [[note]] The plan was very much a product of its time. It called for fighting the enemy on the Soviet-German border and driving them back into Germany, attacking the Germans at every turn rather than mounting what we (and the Red Army of earlier and later years) would consider a proper defense. At the time of the plan's creation, planning for fighting within Soviet territory and defensive actions in general were politically risky because of their association with military academics purged for 'defeatism'. In the aftermath of the purges ''nobody'' wanted to be the first person to find out if going against the anti-defensive trend was going to get them imprisoned (it wouldn't have, but they didn't know that) [[/note]]
** Seeing that papa Stalin ''did'' break the alliance he had with the Reich at the first opportunity it became profitable...
* This is a popular theory for why people allowed the commons in medieval England to be overgrazed. "If I cut back and give the fields time to recover then someone else will just come along and overgraze the field anyways. They'll have better fed cattle and I'll be cut off from a free resource." And that was a real [[http://en.wikipedia.org/wiki/Tragedy_of_the_commons tragedy]].
* Second and Third UsefulNotes/PunicWars were largely the result of both Carthaginians and Romans fearing a future invasion from one another. The second one was started when it became clear to Carthage that Romans weren't going to tolerate their territorial expansions in Iberia for any longer. The third one on the other hand started when what little remained of Carthage after the devastation of the second war was getting back on its legs. Romans started to fear that they might become a threat once again and decided to [[FinalSolution annihilate the entire Carthaginian population]].
* This is the sort of reasoning that [[HobbesWasRight Thomas Hobbes]] feared would dominate people's actions in the absence of an all-powerful ruler whom none could overpower (making it downright suicidal to shoot first, last, or ever). He thought that even genuinely good-natured people would be motivated by worries that their neighbors might not be equally peaceable, leading them to kill lest they be killed (though it should be noted that Hobbes believed ''most'' humans [[HumansAreBastards didn't need this excuse]]).