->''"Minister, Britain has had the same foreign policy objective for at least the last five hundred years: to create a disunited Europe. In that cause we have fought with the Dutch against the Spanish, with the Germans against the French, with the French and Italians against the Germans, and with the French against the Germans and Italians. Divide and rule, you see. Why should we change now, when it's worked so well?"''
-->--'''Sir Humphrey''', ''Series/YesMinister''

A concept in international relations, but one with a lot of relevance in fiction.

To give a hypothetical example, you have five countries:
* A - a Great Power
* B - another Great Power, roughly equal and hostile to A
* C - a lesser power associated with A
* D - another lesser power roughly equal to C, associated with B
* E - another power (Great or lesser) that is neutral

A+C equals more or less B+D, so any kind of war between them would be indecisive or have an outcome that is hard to predict. A protracted war would be incredibly expensive, and bloody, to boot. It's in everyone's interests to prevent or limit A-B conflict.

However, [[KingmakerScenario if E decided to align itself with A or B]], that trio could have a decisive advantage in a limited conflict (before the duo brings their full resources to bear). A protracted conflict between the five would be even more incredibly bloody and expensive than one between the four, however, and its outcome would still be in doubt despite the slight advantage held by one side. Furthermore, it might be in E's best interests to keep A and B balanced against each other, leaving itself free to steer an independent course as neither of the two would wish to drive it into the other's camp by behaving too aggressively against E.

The problem with these arrangements is that not all the powers involved will always have an accurate idea of the other powers' intentions or the relative strengths of all the powers. This can prove disastrous when a power decides to start a war because its leadership isn't in touch with reality.

This trope is a major reason for both {{Realpolitik}} and EnemyMine - A may not necessarily like C, but if both feel B is the bigger threat they will have a good reason to cooperate.


* The ''Manga/OnePiece'' 'verse has a Balance of Power crucial to the overall plot of the story. Types A and B consist of Marine Headquarters versus the Four Emperors (The World Government's military and the four most powerful pirate crews in the world, respectively). In the middle are the Seven Warlords of the Sea, who (on paper at least) are a Type-C, aiding the World Government against the Emperors. However, almost all of them are carrying out their own agendas on the side and some of them have casual and even friendly contact with some Emperors and up-and-coming pirates, making them more of an Type-E in practice. Threats to this balance include single-minded pirates like [[SpannerInTheWorks Monkey D. Luffy]] and the deliberate actions of [[LaResistance Dragon the Revolutionary]].
* Late in the story, ''Manga/{{Naruto}}'' has revealed that the Tailed Beasts, the Bijuu, and their hosts, the Jinchuuriki acted as a balance among the various nations. Konoha and Suna, each having only one bijuu, allied with one another after the last war to deter Kumo and Iwa which both hosted two; Kiri's natural defenses and two bijuu allow it freedom in operation but it lacks the unity needed to take advantage of that. Taki's single bijuu and lesser standing make it an ideal buffer between Kumo and Konoha. Most of the lesser villages align with other villages, have treaties via their daimyo lords, or are located in places where attacks will spark retribution from neighbors. The existence of a free Bijuu would spur other villages to attempt to claim it and gain an advantage, thus necessitating its capture.
** Despite the long time it took to be introduced, this balance was eventually revealed to be crucial to Naruto's backstory. Because maintaining it was [[spoiler:one of the biggest reasons that the Fourth Hokage sealed the Nine Tailed Fox inside of him.]]
* The Vatican Treaty in ''Anime/RebuildOfEvangelion'' dictates that no single country can have more than three active Evas at any given time.
* In ''Manga/{{Beelzebub}}'', the balance lies in the hands of the Tohoshinki, the four strongest delinquents of Ishiyama High, who kept all the other delinquents at the school in check. When Oga defeated all four, he became the strongest delinquent at Ishiyama and united the entire school under his reign. Unfortunately, he destroyed the school not long after. This action would affect the later "Return to Ishiyama" arc, where due to the destruction of the school (which had to be reconstructed ''twice'' thanks to the "Akuma Academy" arc), Oga and the Tohoshinki were unable to keep all the other delinquents in check (the students of Ishiyama were spread out during construction), resulting in a power struggle, where over ''thirty'' groups are vying for the top spot, and aim on taking out them first. Essentially, the main goal of the arc is to put Oga on top again in order to get the school under control, and restore the Balance.

* In ''FanFic/AeonNatumEngel'', the defences of Esoteric Order of Dagon-controlled Iceland are partly based on this principle; neither the New Earth Government nor the Migou can attack without weakening their position against the other, thus stopping them from taking the territory. [[spoiler: Of course, the assumption that the NEG is after the Dagonite-controlled territory turns out to be ''painfully'' flawed.]]
** In ''FanFic/AeonEntelechyEvangelion'' the NEG and the Migou had a status quo for six years since the Fall of China, with no major morale-breaking loses for the NEG since then. [[spoiler:Then Mot shows up and destabilizes the Eastern Front]].

* Some of the intrigue in ''Film/TheGodfather'' comes from the families negotiating about this.
* The United States and the Soviet Union in ''Film/ThirteenDays'' are the A and B. The biggest C's and D's in the movie are Cuba (whose hosting of Soviet missiles was the central issue of the movie) and Turkey (whose hosting of American missiles plays into the negotiations); other players include Chile and Romania (the UN Security Council meeting) and the rest of Latin America via the Organization of American States (unanimous vote in favor of the US [[InsistentTerminology "quarrantine"]]). China and India are also mentioned when the former instigated a border-clash over some mountains in the himalayas--though they don't play a role in the plot itself, their mention even when the Kennedy administration's primary focus was already on Cuba and the Soviet missiles there illustrates the breadth of scope the US had in its foreign policy during the Cold War.

* In ''Literature/TheThirdWorldWar'', the war starts because the USSR is worried about losing D (the WarsawPact) and is won by the West partly because of the role of two Es, namely Ireland and Sweden.
* Oceania, Eurasia, and Eastasia of Literature/NineteenEightyFour; at any point, two are allied with each other, but the alliance always crumbles before the third is defeated because one of the two grows too powerful, and the alliances are reshuffled.
* ''RomanceOfTheThreeKingdoms''
* [[Creator/IsaacAsimov Isaac Asimov's]] ''[[{{Foundation}} Foundation Trilogy]]'' starts out this way. As the Galactic Empire starts to decline, the planet of Terminus is surrounded by the 'Four Kingdoms', who are looking to expand their own influence. They've also reverted to primitive forms of technology though, so when Salvor Hardin, the Mayor of Terminus, lets slip to one of the Four Kingdoms' ambassadors that Terminus still has nuclear power, it looks like Terminus is going to get invaded for its technology. Hardin, the MagnificentBastard that he is, ''also'' let slip Terminus has nuclear power to the other three Kingdoms. None of the four kingdoms are willing to invade Terminus now, under threat of joint retaliation from the other three kingdoms.
* ''ASongOfIceAndFire'' or "How Can Seven Kingdoms Continue To Be One Without The Tyrants Who Welded It Into One Still Being In Charge?" The answer is... finding a new balance is [[{{Realpolitik}}a rather tough process]] with permanent schism very much on the cards. And, that's without Icy Doom coming from the North and Hot, Angry Dragons coming from the East to complicate things.
* The [[SiliconBasedLife Silicoids]] in Creator/SergeyLukyanenko's ''Literature/LineOfDelirium'' are obsessed with the idea of universal balance. This is the core tenet of their culture, and it shapes everything from interpersonal relations to interspecies diplomacy. During the early stages of the [[GreatOffscreenWar Vague War]], they took humanity's side in the conflict, as humans were getting beaten on all fronts. By the end, though, they decided that the new Human Empire was strong enough to keep up the Balance and left.
* In Creator/VernorVinge's ''Literature/TheWitling'', Thengets del Prou and Ajo {{discuss|edTrope}} this at some length; the balance of power on Giri is tenuously equalized between three demographics. It's probably to be expected, considering that almost EveryoneIsASuper. Any two of the major demographics could dominate the third if they united. Prou remarks that if the aristocracies and populace united against the Guild, the Guild would be destroyed, but at the cost of millions of lives. To elaborate:
** The Guild, whose less-than-600 members are incredibly powerful but drastically outnumbered by the rest of the Azhiri, who number around four hundred million. Prou notes that "a single Guildsman can destroy whole cities", and with some quick mental calculations, Ajo realizes he's not boasting.
-->Ajo realized he was telling the literal truth. If a hundred-ton moon rock were exchanged for an equivalent volume of--say--air at Giri's surface, the net potential energy released would be equivalent to a small fission bomb. Perhaps that explained the strange glassy plain Draere had photographed in the southern hemisphere.
** The aristocracies, who command well-trained armies and defensive strategic locations.
** The rest of the population, who pose a threat through sheer numbers.

[[folder:Live-Action TV]]
* One of the central themes of ''Series/{{Babylon 5}}'' is the galactic balance of power between Humans, Narns, Centari, Vorlons, Minbari, and the League of Non-Aligned Worlds. It starts off being about as equitable as might be reasonably expected, but naturally it all turns to custard by season 2.
* In Franchise/StarTrek, TheFederation, [[ProudWarriorRace Klingon Empire]], and [[SpaceRomans Romulan Star Empire]] all see themselves as A with the other two acting as B and E at different times over the course of more than a century. Once other powers like the Borg and Dominion came into play, this balance fell apart. [[CloakAndDagger Section 31]] made it its mission during [=DS9=]'s final season to permanently tip the balance in favor of the Federation.

[[folder:Tabletop Games]]
* ''{{Diplomacy}}'' is practically a research project into this trope. [[UpToEleven With seven A's and B's, whom can devolve into C's and D's as the game develops. And really skillful players could bring them back to A's and B's.]]
* ''TabletopGame/TwilightStruggle'' has the US and Soviet Union as the A and B, with pretty much every other country on the board as potential C's and D's depending on who controls them. The only real E on the board is Communist China, who is represented as a card rather than a space that can be played by one of the powers for influencing other countries on the board (bonus if it's in Asia) and gets passed between each superpower once played.
* ''TabletopGame/{{Battletech}}'', after the Wars of Reaving only 4 clans remain in Clan space. Clan Star Adder-A, Clan Cloud Cobra-C, Clan Coyote-B, and Clan Stone Lion-D.

[[folder:Video Games]]
* ''Franchise/MassEffect'' has Treaty of Farixen, which determines how many dreadnoughts each citadel species may have. Humans, who are limited to 1 per 5 turian, decided [[LoopholeAbuse to build carriers instead.]]
** Sort of subverted: All the powerful treaty signatories (Turian, Asari, Salarian and later [[spoiler: Human]]) are closely allied and the only races that could possibly compete with them (e.g. the Geth and maybe the Quarians and Batarians) are outside the treaty, the purpose of the treaty is more about enforcing the unipolar power of the citadel council races than making any sort of balance of power.
* ''VideoGame/FinalFantasyXII'' has this as a major driving factor behind its plot. What triggers the game's main story is that the balance between two empires, the Archadian and the Rozarrian empires, has been overturned when the Archadian Empire annexes the E power Dalmasca and destroys another one, Nabradia, both of which also served as buffer states between the two empires.

[[folder:Real Life]]
* It has been argued that much of England's and then Great Britain's foreign policy from the 1500s until the 20th century was keeping a balance between France and Spain (and later Germany), to ensure that neither got big enough to take on England/Britain itself. This was explicitly spelled out as foreign office policy in ''Series/YesMinister'', in both past and present. It was claimed the only reason Britain went into the EU was to ensure they could keep the other major powers acting without them. However, ''in reality'' England/GB's Balance-Of-Power 'Policy' has vastly more exceptions than not: the ''only'' wars that actually fit the model are The Napoleonic and Second World Wars. England and later Britain did take a lesson from The Hundred Years' War, but that lesson was not 'prevent formation of continental superpowers', it was '[[RealPolitik don't go to war unless we get more stuff/money from it than we put in]]'.
** Henry VIII did the opposite (joining the strongest side) to try and grab territory around English Calais (where the Valois and Habsburg lands overlapped).
** Elizabeth I didn't want war with Philip II of Spain, Philip declared war on her to put an end to English smuggling and piracy in the Caribbean.
** British-Spanish and British-French wars in the later 17th and 18th centuries were over trade, trade posts, and (to a much lesser extent) colonies.
** Britain ''did'' oppose Russian expansion in The Balkans and Central+Far-Eastern Asia, but only so she could nab The Middle East and India and trading posts in China for herself - Anglo-French Rapprochement (as per the Crimean War) and the Anglo-Japanese Alliance were cornerstones of this.
*** Britain didn't oppose German expansion on principle either, they just did it because it was cheaper than opposing French expansion (because France's Empire was bigger and shared more borders with Britain). This later facilitated an uneasy Anglo-Russian rapprochement when France became Russia's ally in the 1890s, allowing Britain to cut down even further on defence costs.
** Intervention on the side of the Entente in UsefulNotes/WorldWarOne was done to smooth over domestic unrest because Irish Home Rule was about to come into effect and the country was being wracked by massive social unrest instigated by Womens' Rights Activists (who wanted female suffrage) and striking Labour Unions (who wanted an end to child-labour, lethal working conditions, and seventy-hour weeks) - meanwhile, the left wing of the Labour Party was doing its best to channel all of this into Revolution. The 'best' solution - a years-long, cripplingly-expensive War Of Attrition[[note]] Forget 'Home By Christmas', everyone at the top knew what they were getting themselves into. Even the Schlieffen Plan wasn't 'Capture Paris', it was 'get as close to Paris as possible and thereby capture or destroy the bulk of French Industry, which is in the north-east'. To be fair they did manage to capture Belgium, the most heavily-industrialised country in Europe, and a full half of France's pre-war coal supply in just a few months. [[/note]]- demonstrates the seriousness of Britain's 1914 domestic political crisis.
* Some newly found Soviet conversation logs from around 1990 prove that MargaretThatcher was actively opposing the reunification of Germany even when the whole east of Europe was already revolting against the Soviets. Only to keep the Balance of Power intact.
** Confirmed by the diaries of her junior minister Alan Clarke, who was disappointed that she didn't back the reunification he realized was inevitable.
** Even at that time she was quite obviously not in favour of the reunification, so probably no one is surprised about the discovery.
* Pre-UsefulNotes/WorldWarOne Europe was much like this, except that there were ''three to six'' top-tier powers (Britain, Germany, and France at minimum, then Austria-Hungary, Russia, and Italy), with alliances shifting more frequently than you can shake a stick at. On top of that, there were the smaller powers, such as the neutral Low Countries, and the newly-minted and [[PatrioticFervor aggressively nationalistic]] countries of the Balkans (Serbia, Greece, and Romania topping the list in bellgerency and grandiose designs).
* The UsefulNotes/ColdWar was very much about this, although the [[PeaceThroughSuperiorFirepower Superior Firepower]] and MnogoNukes meant that outright war was relatively unlikely. Instead, the US and USSR decided to fight by proxy. There is some variation as both the United States and Soviet Union were so powerful that even if one of them lost a useful ally like China - as per the Sino-Soviet split and Sino-American rapprochement - the balance never shifted firmly in favor of the other side.
** Other countries during the UsefulNotes/ColdWar had become sick of the American and Soviet deadlock and so tried to TakeAThirdOption. Nations such as India, Yugoslavia and Egypt formed the Non-Aligned movement. While UsefulNotes/CharlesDeGaulle had become skeptical of NATO and a pro-American foreign policy that kept France dependent to the Western bloc, to this end he opened trade relations with the Soviet Union, pulled itself out of NATO and developed nuclear potential and tried to constantly veto England's involvement with Continental affairs, factors which made him highly unpopular both at home and abroad. Ironically when France finally had a socialist President like Mitterand, they started moving away from the Soviet Union and drifted towards liberalization of economy and the Western bloc in the 80s.
* For much of its existence, the USSR also had an internal balance of power: the three-way rivalry between the Army, the Communist Party, and the KGB. Whenever one of these elements threatened to become too powerful, the other two would cooperate to weaken it. As soon as the threat was eliminated, the alliance would dissolve.
** The Constitution of the United States similarly invokes this situation among three branches of the Federal Government (Congress, the Presidency, and the Supreme Court), the idea being that if the government is busy fighting itself it can't oppress the people. Historically the leading branch has swung back and forth between Congress (embodied by the Speaker of the House) and the Presidency as the A and B, with the Supreme Court staking its claims to power on occasion as the E starting with ''Marbury v. Madison''.
* The Peloponnesian War represents how the equation can go awry. It was very bad to be an E. Both A & B (Sparta and Athens) decided that the situation was a lot more stable if there weren't any Es around, and generally went about destroying them. Also, it was the Cs & Ds (like Corinth) who started and restarted the war between A & B, figuring that the worse off the superpowers were, the better off the medium powers were.
** Ancient Mayan city-states decllined in a similar way, as well as literal PoisoningTheWell
* Ancient Rhodes, a noted MerchantCity in the Hellenistic era survived by it's expertise in maintaining the balance between the Successor States, and ensuring that it's small but [[BadassArmy extremely skilled navy]] was capable of tilting the balance back whenever one warlord became more powerful then the Rhodians liked.
** Renaissance Venice did this as well between Spain and the Ottomans.
* Wolfers was a political scientist who wrote about how a balance of power is impossible to achieve because, even if it is attained (or roughly attained), it's never in A or B's interest to maintain a situation where they are as powerful as their foe, which means that they fight client wars in spheres of influence and get into arms races.
** Arguably BalanceOfPower is best thought of as a [[BigBookOfWar classic strategy]] to ensure the survival of ''one'' faction (as witness Rhodes and Venice above), rather then a way to keep the general peace. In other words the main point is that other people are [[LetsYouAndHimFight fighting each other]] rather then ganging up on you. The exception, of course, is the modern iteration of the strategy, Mutually Assured Destruction: where if A and B fight, ''everyone'' loses.