Genghis Gambit

""Be it thy course to busy giddy minds with foreign quarrels.""

- King Henry IV, Henry IV, Part 2

OK, so you have a bunch of different factions who fight against each other all the time. Wouldn't it be so much better if they could all get along? Unfortunately, that's not going to happen, as they hate each other's guts.

However, it's said that the enemy of my enemy is my friend. Hence, it follows that if you want to unite people, you must create a common enemy for them to oppose.

This is not for every incidence of enemy factions teaming up against a common threat -- that's Enemy Mine. This is for cases in which a character deliberately creates a common threat for the warring factions to unite against. A False-Flag Operation may help do that, and it can work well when pitched to sides engaging in a Peace Conference, since they've already both proved to be reasonable. Compare Summon Bigger Fish, which usually has less altruistic intentions in mind.

The threat itself is often a Sword of Damocles.

Can be a Sub-trope of Zero-Approval Gambit.

Anime and Manga

 * In Code Geass, . Interestingly enough, . It's In the Blood, it seems.
 * The Gundam Wing manga Battlefield of Pacifists uses a similar idea. An Anti-Villain former OZ soldier wants to inspire deep space exploration by taking a lost Mobile Doll factory and placing it at Mars, suggesting that a force that powerful would force humanity to put aside their differences and unite to deal with the common threat.
 * The centuries-spanning Gambit Roulette of Aeolia Schenberg from Mobile Suit Gundam 00 involved uniting the various factions of the world against Celestial Being.

Comics

 * In Watchmen, the Big Bad plans to force America and Russia to put aside their differences and work together by Whether or not it works on the long run is left up to the reader.
 * In X-Men, Cable once resurrected Apocalypse as a common threat to unite the fractious mutants.
 * Gambit once helped him for the same reason. They're both gonna feel like idiots (just before dying horribly) if Pocky ever wins.
 * Cable turned himself into one of these in Cable And Deadpool. It all works out until Reed Richards calls in to take him down.
 * It should be noted, however, that being . And he still pulled off a pretty sick display of power defending against the
 * In an issue of What If?, Magneto does this to unite the factions of Acolytes battling on Asteroid M.
 * Camelot 3000 AD has an interesting version. The newly resurrected knights are not dealing well with each other, so Kai, who was always the least liked of the knights, chooses to remain in the role by acting like an asshole towards the other knights. Thus he gives the other knights someone common to look down and get along with each other.

Film

 * In Canadian Bacon, the government of the U.S.A. tries to curb economic recession and civilian discontent by renewing the Cold War. When it turns out that Russia is not interested in playing along, the United States government and the media embark on a campaign to unite Americans in a hatred of Canada, of all peoples. Turns out to be a bad idea.

Literature

 * The Trope Namer is Genghis Khan as presented in the Conqueror books, who pulls off an epic, two-way gambit. He starts off by spending the winter raiding Tartar camps so that when spring comes, all the Tartar clans unite to crush this annoyance. He then uses the threat of the united Tartars to unite the Mongols into a single nation, with himself as khan.
 * In The Man Who Used the Unverse, by Alan Dean Foster, what turns out to be this gambit on a galactic scale is one of the final stages of the hero's ultimate plan.
 * Romance of the Three Kingdoms: Yuan Shao wanted Han Fu's territory because it was a source of food for his army. First, he sent a letter to another warlord, Gongsun Zan, proposing that they both attack Han Fu and split his territory. Once Gongsun was on board, Yuan sent a letter to Han Fu, warning him that Gongsun Zan was coming to attack him and that he should accept Yuan as a protector. Han accepts this, at which point Yuan uses his new position to strip him of all real power. When Han realizes he's been had, he flees to Cao Cao's service.
 * Dune: One major theme among the many ploys of Emperor Leto II Atreides. Foreseeing great troubles for humanity, he took it upon himself to unite and prepare them... by becoming the single worst oppressor and tyrant in the galaxy. When, after several thousand years, he thinks it worked, he gladly allows one of the billions of plans to assassinate him to succeed. In a manner he chooses.]
 * Jacen Solo does this in the Legacy of the Force novels. The catch?
 * Illuminatus: Among the (many, many) conspiracies is that the government(s) use this to keep the populace distracted from their own sinister agendas. A character is told to watch China after the USSR falls.
 * Angels and Demons: The Illuminati are used as the enemy of the Catholic Church.
 * Discworld: Magnificent Bastard Havelock Vetinari of manages to pull off an interesting variant; he knows the heads of the various guilds of Ankh-Morpork want nothing more than to see him "dancing the hemp fandango", but the only thing keeping him alive is one common enemy -- an Ankh-Morpork without Vetinari. You don't have to be the BEST patrician to succeed, just slightly better than the alternative.
 * Ursula K. LeGuin's The Lathe of Heaven uses the threat of aliens to unite the nations of Earth.
 * Nineteen Eighty-Four: Global power blocs Eastasia, Eurasia, and Oceania are locked in constant war. The alliances between the three change so that one state can never become too powerful and dominate the others. This is an understanding between the three powers that's been ongoing for decades. The real objective is to provide a focus for their own citizens' hate and Patriotic Fervor -- to unify them, and control them.
 * In Ben Counter's Warhammer 40000 Grey Knights novel The Hammer of Daemons, Alaric sets up a False-Flag Operation to convince people that their overlord had set up the Gladiator Revolt as part of this and unite them for the crusade. Alaric's operation works.

Live Action TV

 * In The Outer Limits TOS episode "The Architects of Fear", a group of scientists turns a man into a fake alien and has him "invade" the Earth in an attempt to scare the nations of the world into cooperation.
 * On a more minor scale, Dr Kelso from Scrubs used this to keep his staff united, by doing horrible things so that they would focus their anger on him rather than each other.
 * Jeeves and Wooster: Jeeves uses this to end the quarrels between Wooster's friends. He tricks Wooster into ringing the alarm bell, thus bringing everyone outside into the pouring rain, where they find out that the door is locked from the outside and they don't have the key. When asked why Wooster rang the alarm bell, he can't give a straight answer, and Jeeves makes him go to somebody else's house to find the key. This gives everybody else the opportunity to unite in anger against him, after which Jeeves "discovers" that he had the key in his pocket all along. When Wooster finally comes back, everybody else just laughs at him for having biked a mile in the pouring rain for absolutely nothing, and forgets that they were angry at him.
 * In the Xena: Warrior Princess episode "Been There, Done That", Joxer decides to invoke this during one loop. He gets stuck full of pointy things for his trouble and ends up taking Xena and Gabrielle with him.
 * In the final episode of Generation Kill, Sergeant Major Sixta reveals that he's been doing this to the battalion the entire time with ridiculous enforcement of the grooming standard to give the Marines an outlet for their stress.
 * Played for laughs in an episode of Sister, Sister. When the girls and one of their friends are all at each others throats, Lisa takes it upon herself to give them a common enemy. She annoys them enough that they're all friends again within minutes.
 * Cutler's plan in Being Human revolves around destroying the facade the vampires have created to hide the supernatural from mortals, then use propaganda to paint the waerewolves as the greater evil and convince ordinary humans to side with the vampires.

Music

 * This is how Shaytan in Seisen no Iberia.

Theatre

 * Wicked: explains to Elphaba that this is what he was doing by making everyone believe the Animals are evil. This is a metaphor for Adolf Hitler.

Tabletop Games

 * Averted in Warhammer40000. Despite all the prerequisites, that is a number of horrible galactic threats of all colors: hordes of Ax Crazy barbarians, Legions of Hell, omnicidal implacable robots, and all-consuming alien locust -- nothing seems to be able to divert the three more reasonable powers from each other's throats. Each power is also riven by internal conflicts.
 * Notice the operative word there -- "...the three MORE reasonable powers..." Assuming the former troper was referring to the Imperium (which will not tolerate ANY xenos under ANY circumstances), the Eldar (who are willing to kill planetloads of non-Eldar just to save one Eldar in ten thousand years' time), and the Tau (who actually are fairly reasonable, in that they are willing to ally themselves with other non-hostile species, but are weak and tend towards being less-than-nice to, well, EVERYONE who isn't an Ethereal), then one can understand why no Galactic Alliance has been formed.

Video Games

 * Starcraft: The Confederacy plans to secretly allow the Zerg to rampage fringe planets as an incentive to keep dissenting colonists in line. Later, Mengsk adopts the same plan and uses it to unite the various factions into a single empire, under his own thumb. Then Kerrigan enters the picture...
 * Knights of the Old Republic 2 revealed that Revan's plan was to.
 * Not quite -- Revan's plan was actually to
 * The Old Republic and associated media make Revan's plans even more labyrinthine, in terms of motivations.
 * Super Robot Wars: Original Generations: This is Bian Zoldark's hidden motivation (and the game that inspired the story arc, Super Robot Wars 2). He organizes the Divine Crusaders in a bid to conquer the world, figuring that either he will unite the world's powers against an alien threat -- or the world's powers will unite against him, either way being better prepared for the invasion to come.

He uses a double-layered version of this trope. He's able to create the Divine Crusaders in the first place thanks to a False-Flag Operation where one of his agents provoked the aliens during a secret Peace Conference, then wipes out both forces. He then broadcasts a speech making it look like the aliens attacked government forces that were planning to surrender to them. So he makes the aliens look like the bad guys so he can unite his forces into being the bad guys to unite the world against the aliens that actually are the bad guys
 * Wild Arms 2: finances the terrorist group Odessa specifically so
 * Final Fantasy Tactics A2 provided a very unintentional version of a Genghis Gambit. One particularly rich individual wanted to start a construction project in the Rupie Mountains and sent various hired hands like House Bowen to evict those clans who refused to step aside. One of the big attractions in the Rupie Mountains is the heated rivalry between the Bangaa Brotherhood and the Nu Mou Nobles. Guess what this individual, via House Bowen, wound up ending thanks to intervention by Clan Gully?
 * Modern Warfare 2: Played terrifyingly straight. deliberately incites a shooting war with Russia in order to
 * In Front Mission Evolved, Cornelius Werner tries this by.
 * Two of the endings in Blood Storm have this happen unintentionally.
 * Discussed and averted in Heroes of Might and Magic IV. A Genre Savvy necromancer rejects a perfectly reasonable plan to conquer one of the newly-emerging nations of Axeoth and rule it along with his own kingdom, because he doesn't want to become the enemy that the rest of the world unites against.
 * In Assassin's Creed, Robert De Sable attempts to persuade King Richard to form a truce with the saracens and unite against the Assassin Brotherhood, since Altair is responsible for murdering several prominent citizens on both sides of the conflict.

Web Comics
"Reporter: So... nations can attack each other with no risk of nuclear annihilation?
 * Saturday Morning Breakfast Cereal: One strip had a hero who tricked the nations of the world into uniting and depleting their nuclear arsenal. It doesn't end well.

Well-Meaning Failure Man: Uh..."


 * Schlock Mercenary invoked this trope here.
 * Except that it's inverted because the threat was totally outside Petey's control. In fact, this is more a case of Enemy Mine than this trope.
 * Order of the Stick: Nale's Father did this unintentionally; he later created a more complicated plan involving a coalition of Men Behind Men working to create three empires instead of one, that are actually working together to stay unified.
 * He does use it on a smaller scale as well as part of that unification plan, using the threat of the other conquering nations to pressure smaller states into capitulating into his empire for their own protection. What they don't know is that his companions control those other major nations and are doing the same thing to gradually absorb every independent state in the region.
 * Bug argues that this is what the UN should be doing.
 * Apparently the reason why  was made immortal in Looking for Group,

Western Animation

 * King of the Hill: Bill becomes the emergency marshal of the local flood shelter and turns out to be a competent and well-respected leader... by blaming Hank for everything that goes wrong and eventually locking him up. Technically, the whole flooding of South Arlen -was- Hank's fault. But Bill had to go and muck it up by keeping everyone effectively imprisoned in the shelter by letting them believe the flood had not yet ended... when it actually had.

Real Life

 * Trope Namer: Genghis Khan, who went on conquests to unite the Mongols. Cracked.com described it as something akin to a massive work team-building exercise.
 * This was Otto Von Bismarck's favorite trick. To unify the many small countries around what is now Germany, he made Denmark look like an aggressor, then manipulated Austria into attacking Prussia, then France into attacking everyone. When the dust settled, Prussia had doubled in size by unifying with all of the small countries, France was humiliated, and Austria was broken. And Denmark lost a chunk of land, as well as a lot of self-confidence.
 * This is the standard operating procedure of fascism: The leaders instill in the people a strong nationalistic pride and militaristic culture, usually hearkening back to the old days when almost everyone fought each other, and then finds an enemy (external or not) and uses them to unite the people.
 * This is a trope common to totalitarianisms in general, not just fascism - Communists use "international Capitalism/Reactionaries/Imperialists", right-wing dictatorships used "Communism/Socialism", religious dictatorships use "atheists/infidels/apostates" and the Nazis used "Judeo-Bolshevism/Jewish High Finance/English Plutocrats (who are also Jews)."
 * Used during the first world war by T.E. Lawrence to unite Arabic tribes. The English army was trying to fight the Turkish Empire, but Lawrence's goal was to create a pan-Arabic nation. Though he did not succeed, he did set the history for the future independence of Arabs from Europe.
 * Not quite. Lawrence didn't give a crap about the Arabs or their independence. He was in it for the Queen.
 * George S. Patton is an inversion of the trope -- he didn't care if anyone was united by anything, he just really fucking loved fighting. It was just good luck he was a good leader as well.
 * One theory is that the entire Arab-Israeli Conflict is, at least in part, the result of Egyptian President Gamal Nassar trying to do this to the entire Arab World. He hoped that by painting the newly formed State of Israel as a common enemy of all Arabs, he would be able to unite the different regional, political, and religious factions under one banner. Unfourtnately for Nassar, the plan failed, and the situation has since taken on a life of its own.

One of the reasons for the original Arab invasion of Israel in 48' (which the Israelis refer to as the second stage of their war of independence) is that the various Arab leaders of the area feared their unpopular regimes would soon face coups, and this was their way of avoiding it. The problem is, the Israelis won, and all of the invading Arab leaders had their governments toppled anyway just a few short years later.
 * Of course, Muhammad essentially executed the trope in an Older Than Feudalism example by converting the constantly-infighting Arab tribes to Islam, which divided the globe into a "House of Islam" and a "House of War"... as in, "we should go be in charge of that to make it House of Islam". They subsequently exploded out of the Middle East, across northern Africa, and even conquered modern-day Spain. They probably only slowed down because they ran out of people who could stay behind and be in charge.
 * Romanian ruler Mihai Viteazul did this as a necessity, as actual enemies (yes, plural) were tearing the country apart in regions. With the rest of them being somewhat subjugated to foreign rulers, he united them by force and succeed, but only for a brief time. Centuries later, Ioan Cuza would do it in a more peaceful and in-accord way, which lasted to this day.
 * Pakistan, with its aid-dependent economy, failing civil infrastructure, religious persecution, and subnationalist movements in every province, generally uses a mild version of this trope. It focuses all the people's attention and hatred on Kashmir and India, respectively, always stopping just short of outright war.
 * This was Hideyoshi Toyotomi's strategy in the 1590s to unite the feuding warlords of Japan: invade Korea and China and let them deal with their carnal fury. They didn't make it past Korea.
 * Conspiracy theorists like to accuse national leaders in general of doing this.
 * Part of the reasoning behind Drill Sergeant Nasty. Even if none of the 40 guys in any given platoon can agree on anything else, they can all rally behind the idea that the bastard sergeant needs to die a slow, painful and embarrassing death...
 * This was the main reason for the Crusades. The struggle of a common cause was intended by the Church to burn away the petty resentments between the Christian lords of Europe, and the land seized was to allow estates for spare sons.