It's time for the second TV Tropes Halloween Avatar Contest, theme: cute monsters! Details and voting here.
"Siamese fighting fish - fascinating creatures. Brave, but on the whole, stupid. Yes, they're stupid. Except for the occasional one, such as we have here, who lets the other two fight. While he waits. Waits until the survivor is so exhausted that he cannot defend himself, and then like SPECTRE... he strikes!"
Why work when you can get someone else to do the work for you? A favored tactic of The Chessmaster
, both villain and Anti-Hero
, is to get two of your enemies to fight each other
instead of you. If one wins, he should be weakened enough from battle that you can knock him off before he recovers.
Most often, this is when the villain decides to let another, unaffiliated villain absorb the majority of the Hero's time and energy. Truly skilled use of this trope is when the villain can break up the Five-Man Band
The Power of Friendship
is a powerful thing. Some villains realize that after getting beaten by it too many times, so they try to somehow split up whatever team of heroes they're facing
. This might involve getting two heroes to hate each other
, getting one hero to hate the others
, or otherwise forcing the team to split up. The Lancer
is a common target of this tactic.
On the opposite side, it's the usual hero tactic when their enemies try working together
. Of course, they're usually much easier to divide, since not only they lack The Power of Friendship
, but they're probably already planning to double-cross each other anyway. By contrast, when the villain sets two groups of heroes against each other, they're much more likely to figure it out and team up.
Compare Let's You and Him Fight
. Contrast Enemy Mine
. #9 in The Thirty-Six Stratagems
, making this one of The Oldest Tricks In The Book
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Anime & Manga
- This is the goal of Yugi in Tenchi In Tokyo.
- In the Yu-Gi-Oh! manga's "Death-T" arc, one of the challenges is a room being gradually filled with huge falling blocks. It's intended to force the heroes to think only of themselves rather than trying to save their friends.
- In Monster, one of Johan's most common strategies is to get different groups of people to fight against one another. In the finale, he has guns distributed around an entire town and gets everyone to start shooting everyone else.
- Naraku from InuYasha tried several times to put Sango against the others by threatening the life (or some such) of her little brother. The first time he managed to make her steal Inuyasha's Tessaiga, but she's gotten wiser since. He also uses various tricks to physically split up the team so he can take them out one by one.
- Team Rocket uses this plan a few times to catch the Pokémon of the episode and almost get away with it until the last minute.
- Code Geass: The strategy Schneizel uses twice on Lelouch: first, to make him believe Suzaku betrayed him by having him arrested during the meeting, and the second time by getting the Black Knights to betray him.
- The description above says "contrast Enemy Mine", but in Soul Eater, Medusa actually managed to Divide and Conquer by means of Enemy Mine. And although she didn't tell them, the people she was "helping" found it obvious that this is her plan.
- In Baka and Test, Class F utilizes this against Class A during a summoner war. They use favors gained from defeating the other classes, or deception in the case of Class C, to have them wear down Class A before the fight. Class F nearly succeeds with it, until the school starts to break down, causing the Class F rep to be distracted momentarily.
- Aizen's plan in the Soul Society arc incorporates large amounts of this. He has Ichimaru let Ichigo's crew escape, so the thirteen squads spend their time and energy fighting them. At the same time he manipulates Rukia's execution to cause splits within the thirteen squads, and after faking his own death manipulates Hinamori into attacking Ichimaru, Kira and Hitsugaya. All of these things manage to divert attention from his machinations, and if it wasn't for Ichigo doing a little better than expected and Captain Unohana realising something was wrong with his 'dead' body, Aizen's plan would have succeeded, he would have escaped scot free and a significant amount of his enemies would be dead.
- This is Baron Omatsuri's M.O. (Carnation Lily, actually) in One Piece. He disguises his island as a resort for pirate crews, where they would play activities and games that are actually designed to cause infighting among the crews. He's so good at this that he succeeds with the Straw Hats, who have an almost familial bond among each other. When captain Luffy finds out about this, he gets so gravely offended that though it's not canon, Carnation Lily is Luffy's first direct kill in the series.
- Bane, of Batman extraction, is legendary for this. Aware that he couldn't take Batman in a straight fight, he instead released dozens of inmates from Arkham Asylum, leading Batman to run himself ragged for months until Bane showed up in the Batcave and "broke the Bat."
- In one issue of Incredible Hercules Malekith combines this with Let's You and Him Fight to weaken both Hercules and Thor sufficiently that his secret weapon will be able to defeat them easily. His plan fails ignominiously due to him not being aware that Zeus was standing right there when he sprang this trap.
- In Asterix and the Roman Agent this is the natural gift of the titular Tortuous Convolvulus (French: Tullius Détritus), who foments conflicts between the inhabitants of the little Gaulish village that come close to enabling Caesar to take it.
- In My Little Pony: Friendship Is Magic (IDW) the changelings separate the group with a cave-in and start causing feud between them through the use of disguises and personal insults. It works.
Films — Live-Action
- This is a key element in A Fistful of Dollars
- Used in Serenity, where Mal pits the Alliance and the Reavers against each other to buy enough time to broadcast the secret of Miranda to the entire verse.
- And in Lucky Number Slevin, which is unfortunately a huge spoiler. Slevin had been playing a con the entire movie to kill both the mob bosses by setting them against each other. He also puts himself in the middle of it by appearing like a harmless bystander, but eventually he gets his revenge for the murder of his parents, two decades in the making.
- James Bond has a lot of it. Three deal with USSR x USA, From Russia with Love - source of the page quote -, You Only Live Twice and The Spy Who Loved Me (first two are Blofeld-lead SPECTRE).
- Also, the Joker's strategy: get Batman so riled up with the Black and Grey Morality, fighting the police and trying to redeem Harvey Dent, he can barely take on the Joker.
- In the Film of the Book The Sum of All Fears, "You don't fight Russia and America. You get Russia and America to fight each other... and destroy each other."
- The Hellfire Club tries to do this by engineering the Cuban Missile Crisis in X-Men: First Class.
- Done to the two rival gangs in Desert Heat. Naturally, considering it's an adaptation of Yojimbo.
- In The Thing (1982), The Thing realizes it can't win against a united camp, so it tries to sow paranoia and distrust among them. It frames Macready as a Thing to keep the remaining humans from being united under his leadership and assimilates Norris and Palmer, the two least likely to be suspected as Things.
- This joke emerged not long after the Global Financial Crisis struck:
A CEO, a Tea Party member and a public employee sit at a table, with 12 cookies on a plate. The CEO grabs 11 cookies and tells the Tea Party member, "You better watch him. He wants your cookie."
- May not be entirely accurate, but Mordeth in The Wheel of Time seems to have managed to pull this on an entire city.
- In Outbound Flight, this is sort of what Commander Thrawn did. Sort of. Due to his Batman Gambit, the entire Vagaari fleet came out of space near where Outbound Flight was trying to decide what to do about him. The Vagaari being probably the most unambiguously evil side Zahn has ever written, they attack Outbound Flight, and the Jedi at its weapons stations sense the Living Shields on the outsides of the ships, so they use the Force to more or less scramble the minds of the Vagaari. Then Thrawn triggers the second programming level in the droids he'd arranged to be on the Vagaari ship so that they slaughter the Vagaari high command, while also cuing the droid starfighters to buzz the Vagaari ships and shoot between the hostages. Being in such close contact with beings being slaughtered en mass, the Jedi are stunned and can't react in time to prevent Thrawn shooting out all of the weapon stations, killing most of them.
- Outbound Flight wasn't his enemy in the same way that the Vagaari were, even if its commander took an instant hatred to him. If that commander hadn't been a budding megalomaniac, or if Thrawn hadn't followed his standard policy of shooting out the weapons systems of anyone who he distrusted but wasn't all-out enemies with, the major problems probably would not have happened.
- This is how Joshua leads the Israelites to take over most of Canaan in The Bible.
- In the first book, Wen Chao keeps up hostilities between the Mongols and Tartars to keep both sides weak and thus allow the Chin to extract tribute from them. Unfortunately for him, the Mongols manage to win the war under Temujin, who quickly ends the practise.
- In the second book, the Chin emperor refuses to send aid to Emperor Wei of Xi Xia when the latter is attacked by the Mongols, specifically saying that it's better for one's enemies to fight each other.
- The entire point of Tom Clancy's The Sum of All Fears, where Arab nationalists nuke Denver in order to start World War III between US and USSR. It nearly works, despite the fact that there is no reason to suspect the Russians given the lack of a missile launch, built primarily on President Fowler's personal dislike of Jack Ryan, and assisted by former East German Stassi agents working with the terrorists posing as officers in the Red Army, and trick a tank brigade in East Berlin into attacking an American base in West Berlin. Those involved in the terrorist plot are also unwittingly helped by an American mole in the Politburo whose been feeding the U.S. false information in the hopes of destabilizing the current government in the USSR so he can grab power for himself.
- Inverted in Isaac Asimov's short story: "In a Good Cause". where the wars amongst humans actually made them stronger, which gives them the upper hand against the united aliens.
- Militarily stronger, that is (and — which turns out to be an important plot point — only if no faction on the divided side decides it is a better bet to support the united side). It is acknowledged that being united is generally a preferable state, and in fact the seeming turned opponent to human Federation at the end reveals that he still wants it, and now that the aliens have been defeated, the situation is right for such a call to be made and heeded.
- Inverted in Harry Turtledove's World War series, as the invading aliens' millennia-old unifications means their technology has been purposely stagnated by the government to prevent disruptive changes in society, while humans being disunited and constantly at war with each other means we're able to change much quicker.
- This is the strategy David from Animorphs uses once he goes Sixth Ranger Traitor. Well aware that he's just one morpher against six, he opts to split the team up and take them down one by one. This strategy is wildly successful, and leads to him defeating (and very nearly killing) four of the six Animorphs in a single night.
- The "true" villains of A Song of Ice and Fire, Varys and Littlefinger, both do this in order to further their goals. Both of them work to instigate a civil war between the various houses of Westeros, having them destroy each other so that they have little chance of ultimately opposing their goals. And when things appear to stabilize, they just give another light push to get things to fall apart again. The difference between Littlefinger and Varys, however, is that Varys is creating the power vacuums for House Targaryen to take back the throne, while Littlefinger is aiming to take over Westeros for himself.
- Buffy the Vampire Slayer: Spike (inspired by The Beatles) tries it at the end of Season 4 at the behest of the Big Bad Adam. Unfortunately, another part of Adam's plan involved them sharing information. So he then had to convince them to talk to each other again, whereupon they reconciled.
- This is the official motto of a league of assassins, the Order of Taraka.
- The number of times they've done this in Power Rangers is beyond counting. Often more than once in the same season.
- Michael pulls one of these about every third episode of Burn Notice.
- The Twilight Zone episode " The Monsters Are Due On Maple Street", aliens do this, taking advantage of the fact that Humans Are Bastards. An ordinary street, in an ordinary town, suffers a sudden and inexplicable power outage, with a few suspicious items still functioning. The neighborhood gets together and comes to the somewhat strange conclusion that alien invaders are messing with things, and then start accusing each other of being in league with the invaders. End result: mass hysteria. Cut to two Human Aliens on a hill overlooking Maple Street, marveling at how they won't have to fire a single shot, the humans can easily be tricked into killing each other!
- In Stargate Atlantis, McKay reactivates the Replicators' programming that causes them to attack the Wraith. Unfortunately, it backfires a bit when the Replicators determine that the most efficient way to wipe out the Wraith is to eliminate their food supply.
- Sir Humphrey Appleby in Yes, Minister mentions (as we see in the Real Life section below) that this was British policy in decolonization to "keep us from having a policy about them."
- In the eighth season finale of Bones, Christopher Pelant uses this tactic on Booth, blackmailing him by threatening to go on a new killing spree if he married Brennan. The season ends with Brennan and Booth both devastated, and Booth unable to even tell her why he had to break off their engagement.
- In Lexx, His Divine Shadow the last survivor of the Insect Civilization used this strategy to defeat his true enemy humanity. He set up a brutal theocracy centered around slavish devotion to himself. After thousands of years, most of the humans in the Light Universe were under his rule, with resistance all but stamped out. By the end, his followers were so indoctrinated that they literally fed themselves to him when he asked. In his own words, he "used humans to defeat themselves."
Myths And Folklore
- One of Aesop's fables tells of a lion who was unable to hunt down a herd of cattle since the cattle would always stick together as a group. That is, until the lion gets the idea of spreading gossip among the cattle to get them to fight and seperate allowing said lion to attack the cattle one by one.
- Any good Risk player has done this.
- Paranoia: Friend Computer would like to remind all citizens that this is an effective way of dealing with commie mutant traitors. Also that knowledge of such techniques is treason.
- In The Golden Apple, Ulysses invokes this tactic by name, splitting the people of Rhododendron on the issue of Helen to win her back from them.
- In Margin for Error, Otto Horst claims that this is his best propaganda strategy for Nazism in America:
Horst: No, Baron, my best bet is to create conflict among creeds and colors. Then step in, when they're exhausted, and take the whole country over—bang! Next week I attack the Catholics, Masons, Negroes, and Café Society.
Max: Perhaps you'd better just purge Elsa Maxwell, and leave the rest to Hitler.
- Very common tactic players use in video games that allow NPCs to fight each other, such as Half-Life (letting Combine fight Zombies, HECU to fight aliens) and Halo (letting the Flood take out the Covenant). It can be traced back at least as far as Doom, where "monster infighting" was crucial to beating some parts. Doom 2, for example, has a Spider Mastermind and a Cyberdemon right next to each other. The only effective way to survive is to get them fighting each other.
- There's an entire room devoted to this in Doom 2's eighth level, "Tricks and Traps". Fifty Barons of Hell, one Cyberdemon... four Invulnerability Orbs. Grab an Orb, get their attention, and hope that the Cyberdemon can take out most of the Barons before the weight of numbers kills him.
- Sturm attempts to do this in the first Advance Wars. He tried to get the nations of Orange Star, Blue Moon, Green Earth and Yellow Comet to engage in a brutal war that would leave all sides devastated, so he could sweep in with his own forces and conquer all of Wars World.
- Kerrigan does this to everyone in Starcraft Brood War.
- Devil May Cry 3: Jester/Arkham.
- Any Pit player worth his weight in salt does this as well when deploying Palutena's Army in Super Smash Bros. Brawl. It's one of the few Final Smashes that allows the user to move and act freely with his own moveset during its execution. The reason it falls here is that the Centurions are dangerous in their own right, and the player has to choose to either focus on dodging them or dodging Pit, though a skilled player can do both for the most part.
- By the end of Kingdom Hearts II, Sora is too busy dealing with the Nobodies and Organization XII to properly deal with Maleficent, Pete and the Heartless.
- Ace Combat 5: The Unsung War has this as the driving force behind its plot. 15 years before the game began, the country of Belka tried to take over the world and failed, eventually setting off 7 nuclear weapons on their own cities to stave off the approaching allied forces that included Osea and Yuktobania. In the present day, Yuktobania attacks Osea, and the two are plunged into a bitter war that drags on until nobody can remember why they're fighting. After the player's squadron is betrayed, the truth is revealed: Belka, the country that was defeated 15 years earlier, was behind the whole thing. They started the war in hopes that it would eventually exhaust both of the other superpowers, and helped to escalate it at several key points. After rescuing the Osean president and Yuktobanian Prime Minister (and getting them to stage a peace rally in order to end the war), the Razgriz Squadron takes down the Belkans' last superweapon, ending the threat for good.
- An element of gameplay in Final Fantasy XIII. Because of the different alignments enemies can have (Cocoon monsters, Pulse Machines, Pulse Monsters), occasionally the player will find two factions of monsters fighting each other. They can then fight the stronger enemy alongside the second enemy, then when the first enemy is defeated, the second enemy is weakened.
- In Silent Storm, Thor's Hammer is trying exactly that with the Allies and the Axis. While they didn't start the war, they are taking advantage or it by supplying both sides with advanced weapons, while keeping the best goodies for themselves.
- In Haegemonia: Legions of Iron, the Darzok use this method to break up their enemies. They convince a Kariak general to rebel against the Human-Kariak alliance, allowing them to build up their forces while the Kariak fight among each other.
- Probably one of the better ways to deal with enemies in BioShock, particularly the Big Daddies. Just casually goad a Splicer into attacking you while you're standing near one of the lumbering Daddies. More than likely one of their attacks will hit him instead of you, and after that you can honestly just slide on over to the sidelines while they go at each other.
- In The Elder Scrolls V: Skyrim, this is what the Thalmor's tactics are presumed to be and confirmed when you find out that Ulfric Stormcloak is a Thalmor asset. In the Great War, the Thalmor, fought to a standstill by the Empire, made a peace treaty with terms that the provinces would never agree to (ceding half of Hammerfell and outlawing Talos worship). As of the time of Skyrim's story, Hammerfell has seceded from the Empire and Skyrim erupted into civil war, meaning that the Empire is now a much weaker target. Despite this, they don't want Ulfric to actually win, but merely wish for the Civil War to weaken both the Empire and Skyrim.
- In Neverwinter Nights 2, there is a section where a group of Fire Giants want to kill a nearby Dragon and the Dragon wants to kill the Fire Giants that have been harassing it. They both request your aid to deal with the other, and they both have something valuable that you may wish to take (for the Fire Giants, it's a quest item. For the Dragon, it's a massive pile of gold). No matter who you ally with, in the end you're given the option to betray both of them and let them duke it out with each other. Whichever side survives will be in a weakened state, thus allowing you to easily finish them off.
- BlazBlue: The seat of "Ministerial Secretary to Jin Kisaragi" falls into this trope due to its effects on two of the girls involved. This was deliberately invoked by Hazama / Yuuki Terumi to make both girls more compliant with his whims, and for the most part it worked.
- Noel Vermillion was offered the seat six months prior to her graduation as a means to restore prestige to her family, and took it with the blessing of her friends. This is a bad thing, since Jin had come off the war a massive jackass (well, more than prior), and used her as a means to vent his frustrations. This was for the sake of mindraping her into the Sword of the Godslayer at a later time, using Jin's horrid mentality and ingrained disdain for her as a means to wear her down, going so far as to cut her off from her two friends.
- Tsubaki Yayoi, who was more competent at this role (and who was originally supposed to receive it), was delegated to the Zero Squadron instead. She loves Jin, but could not follow, and was left "cleaning up the trash". A side-effect of Noel getting the job was that Tsubaki would become lonely due to being cut off from her friends and harbor jealousy over Noel getting the job, and this was his in-road to mindraping her into a Brainwashed and Crazy loyalist to the NOL. In the end, Tsubaki tries to accost Noel over the resulting jealousy, going so far as to try to kill her.
- An important thing to note is that this conflict is so integral to the plot of BlazBlue: Continuum Shift that if anyone - anyone - were to mend the girls' psyches, everything would fall apart. Fortunately, just about the rest of the cast is indifferent to or despises Tsubaki, indifferent to or despises Noel, could give a shit less about them both, or is exploiting their relationship for their own ends. The exception is Makoto Nanaya, their common friend, who signed on with NOL Intelligence and proved dangerously competent at her job, forcing Terumi to send her to Ibukido, her assignment meant to dead-end her job or have her killed from seithr overexposure or cauldron timefuckery. Even THAT failed to do her in, and instead made her even more dangerous to the overall scheme, forcing Hazama to take matters into his own hands. As proof that the entire plot was completely brittle to Makoto's touch, in Arcade mode Terumi interfered after Makoto knocked Noel out to move the poor girl into the tempering phase ahead of schedule - he literally had no choice, as Makoto was going to talk some sense into Noel after she came to, and had subdued Tsubaki earlier to keep her from killing Noel. Suffice it to say he didn't take it well.
- Galactic Civilizations 2 is known for its rather ruthless and diverse AI (which only cheats if you ask it to). It has been known to produce some Magnificent Bastard moments, where one AI empire will not declare war on you, but instead convince/bribe two (or more) other empires to do so. They tend to mock you in your moments of death (should you be killed) by revealing this fact. And it doesn't even know who the player is, so it even pulls these on other AIs.
- In Mass Effect this is the M.O. of the Reapers, the big bulletpoint at the top of the plan behind every invasion. Starting by using the Citadel to decapitate galactic governments, followed by shutting down the Mass Relays to isolate systems from one another so they cannot receive help. Nevermind their Indoctrination tricks to further divide those who oppose them long before the Reapers actually appear on the field. It's a brutally efficient demonstration of the trope. If not for the Protheans deciding to throw a Spanner in the Works, who knows how long the cycle could have gone on for?
- Not a gameplay element, but Caesar from Fallout: New Vegas cites this as how he was able to take the puny Blackfoot tribe ... and conquer 85 others. This is a deliberate homage to the Real Life Caesar, as is the entire nation he's trying to found.
- Seems to be the main strategy of the Big Bad, Snadhya'rune Vel'Sharen, in Drowtales. She doesn't have enough followers to take over the Drow race uncontested, so instead, her agents have been secretly manipulating all the major factions across the underworld into destroying one another so that she can fill the power vacuum.
- Happens all over the place in The Order of the Stick. First you have the Inter Fiend Cooperation Commission, who seek to keep the battles between The Order, The Linear Guild, and Team Evil going as part of their Gambit Roulette. On a smaller level, General Tarquin is poised to take over the entire Western continent this way. In an inversion, he's going to keep the continent split amongst himself and his confederates so that no one country is seen as a threat or a tempting prize.
- In The Gamers Alliance, the mage Jemuel plays both the Grand Alliance and the Yamato Empire against each other during the Great War in order to carve his empire while the two are busy fighting. He succeeds, crushes the remaining Yamatian troops in the kingdom and frames the Alliance in the eyes of the populace for causing a catastrophe which has devastated a part of the continent.
- Divide and Conquer has been a tried and true tactic of empires throughout history. The Other Wiki has a more comprehensive explanation of Divide and Rule and its uses.
- This was the favorite tactic of Julius Caesar, arguably the Trope Namer. His motto was Divide et Impera, which translates to "Divide and Rule"note . Caesar would ally with one tribe in Gaul (modern France) and pit them against others to win. This was the reason the Gauls lost, or at least it sure helped.
- This has always been characteristic of Roman conquest, since their early wars within Italy. Once conquered or "allied" a city-state would be bound by contract to Rome and forbidden to form any kind of alliance (including marriage) with their former allies. By the time Rome controlled the whole of Italy, they had over 150 contracts with various states, none of which had any formal links to one another other than as allies of Rome.
- The war between the Eastern Roman Empire and Sassanid Persia that took place from 602 to 628 weakened both countries so much that the Arabs were able to invade and conquer all of Persia and half of the Eastern Roman Empire. The Arabs did not actually instigate the conflict, as they were still a disorganized bunch of tribes, but they took advantage of the situation, being united under Islam soon afterwards.
- Henry VII, in order to eventually subjugate the Irish clans, used a ploy called Surrender and Regrant. Any Irish tribal leader who swore loyalty to Henry ("Surrender"), would be given their lands back, plus an English aristocratic title ("Regrant"). English titles are inherited by the eldest son (or nearest male relative), where as Irish clan titles were inherited by a successor chosen by a representative body of the clan. This meant that, further down the line, the inheritance would fought over between the claimant under English law and the claimant under Irish clan law, giving the English an opportunity to "intervene".
- This is also the primary reason that tiny expeditions of conquistadors were able to single-handedly obtain victory over entire American subcontinents, by sowing confusion and playing different native powers against each other. (Smallpox and guns helped, too.)
- Jiang Jieshi's schtick, and that of his eventual rival Mao Zedong. Both were shrewd and calculating politicians, and used this strategy to great effect as they bribed, back-stabbed, assassinated, out-cliqued and out-manoeuvred their rivals in their scrambles to be the top dogs within their party-factions-governments. Likewise they maintained their power in this way: both played on factional rivalries to safeguard their own positions. The problems with this kind of government became apparent during the course of the post-WWII Civil War when Jiang's paranoia, heavy workload, and military incompetence came to a head: when taken with Jiang's poor administration and strategic decision-making, the Army's lack of co-ordination - due to factional rivalries and the resultant lack of coordination between Armies, Divisions, Brigades and sometimes even the Battalions within them - proved fatal. Once Mao's armies broke his line at the Yangtze and swept into South China, the majority of Jiang's remaining forces defected or simply melted away. For his own part Mao learned not to tolerate any kind of factionalism within the Army, though he continued to Divide and Conquer his political would-be/could-be/might-be rivals well into the senility of his old age.
- The Dutch, French and English East India Companies had low (think 10%) and ever-decreasing numbers of European personnel which eventually, after the Sepoy (Indian Soldier) Rebellion of 1857 resulted in the English East India Company being dissolved and and replaced by the British Raj, which directly administered two-thirds of the subcontinent's territory and population with an Indian Civil Service of no more than 2000 men. Only the very top level of the administration was British, and the remaining third of the subcontinent was governed by states loyal to the British Crown
- A literal example occurred during The American Revolution, when Britain tried to take over the Hudson River valley in order to physically cut off New England from the rest of the Thirteen Colonies.
- Bismarckian Germany did the same thing in the late 19th century, keeping France isolated from their natural allies, Russia and the UK.
- While Bismarck's policy of keeping France isolated (which included a secret Russo-German treaty) may be interpreted as an example of this, Russia and the UK cannot by any stretch of the imagination be described as France's natural allies. France and the UK had in fact continually been at war for centuries and within the past century France had waged several wars against Russia (the Napoleonic Wars of the Second, Third, and Fourth coalition, the 1812 Invasion, the Wars of Liberation and the Crimean War) and their one notable alliance (1807-1812) had turned sour very quickly; France was also traditionally sympathetic to Poland. At Bismarck's time there were some pretty serious collisions of interest between Britain and France (especially in the carving up of Africa) and Britain and Russia (e. g. over Central Asia and the Dardanelles), but no direct conflicts of interest between Germany and Britain or Germany and Russia. This changed after the end of Bismarck's chancellorship as under Wilhelm II Germany took a much more active role as a colonial power, expanded its navy enough to cause concerns in London, and let the relationship to Russia cool off by supporting its ally Austria-Hungary in the Balkans.
- Red October and the fall of the Czarist and Provisional Russian governments was effectively due to Germany successfully using public discontent to undermine the power of the Pro-Allies factions in Russia in the hopes of reaction against them that would open the door to a German-dominated Eastern Europe.
- A big part of why Japan was able to just seize Manchuria from its warlord Zhang Xueliang in 1931, nab bits of Inner Mongolia from 1931-37, and occupy the North China Plain without too much hassle from 1937-45. Chiang Kai-Shek tested his forces against those of Japan in the 1932 Battle of Shanghai and, with their horrible performance, saw vindicated his conviction that he would have been unable to contest the Japanese annexation of Zhang's territory in an open war. He immediately ordered a massive program of armament that could well have seen his army very-nearly on-par with that of Japan's by 1942, and strove to avoid a war until then - given the nature of his Nationalist Party regime it's hard to imagine him not declaring war on them eventually. When the war did break out in 1937 and his half-reformed forces were driven off the North China Plain and the Lower Yangzi, the Japanese allowed the Chinese Communist Party to basically take control of all the areas of the plain that Japan didn't want and/or couldn't control - the two maintained unofficial truces throughout the war, with the sole exception of a brief battle in 1940 ('the Hundred Regiments offensive') which had been ordered at the insistence of Joseph Stalin.
- The German-led Axis took advantage of this during their invasion of Yugoslavia in WWII by rallying the country's neighbors to help invade and by arming the radicalized minorities (most notably the Croats with some Slovene, local Hungarian, and Albanian support) against the Serbian-dominated Royal government. It worked devastatingly well - probably too well, if the subsequent bloodshed and the resulting rise of the Partisans and the Chetniks and their effective tying up of hundreds of thousands of Axis troops shows. Some of the Croatian groups the Nazis stirred up were also such fanatically brutal killers that even SS death squads were sickened by them, and left the Serbs burning for revenge...
- The Soviets tried to do this throughout their history (and started before the Soviet Union even existed yet) by trying to drive wedges between their enemies, whoever they might be at the time. In World War One, they tried to pull Germany, Austria-Hungary, Bulgaria, and the various White Factions apart and incite revolution in at least one of them. Before, during, and after World War II, they believed that pitting the West against the Germans would leave a power vaccum that would effectively cement Soviet dominance (which was thwarted by Hitler's paranoia and decision to strike at the USSR first). And in the Cold War they generally tried to keep the West and the Chinese from coming to any kind of agreement while trying to undermine the solidarity of the Western powers themselves.
- This was countered by United States opening up (relatively) friendly relations with China despite their ideological incompatibility, as each considered the Soviets to be the greater threat (America seeing them as such because the USSR was simply more powerful than China, and China because the USSR was literally right next door to them).
- North Korea pursued a strategy of playing the Soviet Union and China against each other, ensuring that North Korea would always be backed by a major communist power whilst also avoiding becoming a subservient puppet state to either country. The Great Politics Mess-Up was a huge disaster for North Korea, since it meant they were now stuck with China and couldn't periodically switch their loyalties to another communist power. The solution? Nuclear weapons!
- The United Kingdom was quite successful in this in their centuries-long struggle with France. Usually that took the shape of creating a balance of power in Europe by supporting France's enemies, which kept the French occupied and enabled the British to conquer their enemies' overseas possessions. In some cases Britain would then get out of the war after achieving their aims, much to the chagrin of their erstwhile allies, e. g. in the War of Spanish Succession and the Seven Years' War.
- Talleyrand was a past master at this. As Napoleon's foreign minister he managed France's successful diplomatic efforts to prevent e. g. Prussia from joining the Third Coalition (which it came close to after French troops had violated Prussian territory) and Austria the Fourth. In 1813 and 1814 Napoleon by his intransigent refusal to make any concessions at all forged the coalition of Britain, Russia, Prussia and Austria and also ensured that it would not break up before his abdication. But during the subsequent Congress of Vienna Talleyrand once again played off the other powers against each other (mainly Britain and Austria against Russia and Prussia) and secured terms more favourable to France than most would have dared to hope for.
- Large companies have been known to do this as well. During the Great Southwest Railroad Strike of 1886, Railroad Baron Jay Gould allegedly boasted that he could "hire one half of the working class to kill the other half."
- In recent years, divide-and-conquer has been used in Culture War politics by spin doctors such as Karl Rove and Lynton Crosby, in the form of 'wedge politics' (or dog-whistle politics in Australia).
- During decolonisation, The British Empire used partition three very notable times:
- Partition of Ireland into the Irish Free State (later the Republic of Ireland) and Northern Ireland in 1922,
- Partition of The Raj into India and Pakistan in 1947, and
- Partition of Mandate Palestine into Israel and Palestine (although the second bit didn't get off the ground) in 1948.
- Arguably, the manner in which Yemen was decolonised counts as well, although that's a more complicated story.
- Why? Well, as it turns out, Yes, Minister isn't that far wrong: the Foreign Office, recognising that Britain could no longer hold on to these territories (or in the case of Ireland, most of it), still wanted to maintain some semblance of British influence without being too bothered about the details. So they set things up so they could play powers against each other when they wanted to be engaged, while allowing them to formally "deplore" all the nastiness on the ground (recall that even in Ireland, the formal British military and police were not the major violent players on the Unionist/Loyalist side except at the height of The Troubles).