Why "In politics, the tripod is the most unstable of all structures"?

Question

In Dune, Frank Herbert writes that "In politics, the tripod is the most unstable of all structures", in reference to the dominant power structure in the book: Guild, Imperial House, and Landsraad.

I've always puzzled over this statement because it isn't intuitive to me. In physical structures, triangles and tetrahedra are the strongest. A tripod can stand on uneven surfaces and doesn't suffer from the "wobbly table" problem.

Even in politics, it seems that three factions is a self-stabilising structure, because there is a strong incentive for the two weaker factions to cooperate; if they let the strongest faction eliminate one faction, they're next. In history you can find many examples of this happening, and either the weaker factions switch sides depending on who's the strongest at the time, or the strongest becomes unstoppable.

So is Frank Herbert referring to some specific political theory? Or is Dune's tripod somehow different to real-life tripods, and is unstable instead?

Answer 1

The tripod is truly the weakest political structure

The balance of power in a political tripod is only stable as long as everyone wants to win and all players would rather prefer the status quo to a high risk game.

In game theory this is the typical situation for board games with 3 players, where only one player will win the game. The two weaker players will always gang up on the strongest player so that player doesn't win.

But a real world political tripod is a lot different. Because there is no universal rules of "winning" there can be a lot of scenarios where two players gang up on the third to eliminate that player. As soon as two players become power hungry enough they can ally and destroy the third to split that player's goods.

Another common scenario is the strongest player convincing the weakest to destroy the runner-up. In this case the weakest player will become the second in command to the new emperor after the only real danger (the second strongest) is destroyed.

The third scenario which is likely to occur is when two players hide their true strength and each one is confident they can take the other in a 1-on-1 confrontation. Then they will gang up on the third player, eliminate that player, and hope to take power in the resulting face-off.

It is ironic that the political tripod is in contrast to the strong mechanical tripod actually the weakest political structure. It takes only a single common cause for two players to destroy the third, because the forces of two combined are most likely enough to overpower the third without much risk.

A single absolute power is quite stable (the 1000 year reign of Leto). Two powers keeping each other in check is also quite stable, because each one would have to risk everything to attack the other one alone. One side needs a massive advantage to feel at least twice as strong as the enemy to win in a quick assault.

If you have more than three members you need a bigger number of allies to band together to eliminate a single member, as soon as there are three members in an alliance the alliance is internally a tripod and becomes unstable - each suspecting the others of treachery. Also it is harder to find a common cause to unify more than two factions without infighting. And without a vast majority it becomes too risky to try and take on 2 player together with 3 players.

The tripod is the only structure where a single alliance between two players is enough to almost guarantee victory over all other factions (namely the third player)

Answer 2

You actually have the answer in your question. Three legs together are very stable, yes, and two sides will act to balance out the third. In Dune, there are three groupings that keep one side from taking all the power:

• The Emperor and the Landsraad keep the Guild from becoming too powerful
• The Landsraad and the Guild keep the Emperor from becoming too powerful
• The Emperor and the Guild keep the Landsraad from becoming too powerful

Inherent in this balancing act is that each of the three legs are of almost equal power. If one of the three sides of the tripod is made weaker or stronger in any way, the balance is destroyed.

Paul Atreides used the leverage he had over the Spacing Guild due to his control of the spice to weaken the guild, and thus was able to take on the emperor. When Paul took over as emperor, the position of emperor gained more power than before politically and commercially by combining the assets of Houses Atreides and Corrino. By diminishing one leg of the tripod and strengthening another, Paul Atreides tipped the balance of power to favor him and his house.

Even though he was still opposed at the beginning, by using his leverage over the Spacing Guild, he cemented his power, and then grew it even more. Any of the Houses Major and Minor that opposed him, he defeated, and took their holdings. House Atreides eventually wound up with 51% of the CHOAM shares and substantially diminished the power of the Landsraad.

This culminated in Leto becoming God Emperor, with all of his political opponents reduced to scheming in the shadows for thousands of years.

Answer 3

It is just an historical reference.

The most famous triumvirates are those of Rome (up to the point that you name them "First Triumvirate" and "Second Triumvirate", and everybody understands what are you talking about even if you do not add the "Roman" adjective):

• The First Triumvirate was between Julius Caesar, Pompey the Great and Marcus Licinus Crassus. Crassus died in an ill-planned campaign in Parthia (seeking the military glory that the other two already had), Caesar and Pompey fought each other in a civil war which ended with the later dead, and Caesar was assassinated shortly thereafter. Not promising.

• The Second Triumvirate was between Caesar "heirs", Octavius (later Augustus), Mark Antony and Lepidus. Lepidus was the first to break away, but he was only exiled. After that came the showdown between Octavius and Mark Antony, which ended with Mark Antony defeat and death.

• Other possible reference is Napoleon's triumvirate (which had him as the "First Consul" and ended with him as "Emperor", therefore dissolving the triumvirate)

So my bet is that Frank Herbert just wanted Paul to be against the idea of a triumvarate, and hope that the reader¹ was knowledgeable enough in history to assume that past experiences (at least the most famous of them) prove that triumvirates are always a bad idea, by themselves).

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¹Obviously, in-universe Paul would not have known about those -or perhaps he did because of his access to his ancestors memories, but that is not the point. Herbert assumed the references would be too obvious as too garant any discussion.

Answer 4

I think maybe I misunderstood the quote.

The structure itself is stable and self-reinforcing, as the question argues, but it's rather the shifting alliances that is unstable.

As previously mentioned, there is a strong incentive for the weakest faction to be allied with the weaker of the other two. Whenever the relative power of the top two factions change, the weakest side also wants to switch sides. For the stronger two sides, there's a conflict between wanting to become more powerful, and appearing to be too powerful so that the other two sides ally against yourself. This setup fosters deception and unpredictability; you never know who might backstab you, or sit back and watch the other two factions wear each other out.

Answer 5

There are a lot of issues with a "tripod" in politics. Remember that politics is not like a stood. The legs are not rigid. They are energetic entities attempting to optimize their own life goals. They act nothing like wooden legs.

One classic example is in electoral politics. You'll note that its very common for there to be two parties in a parliamentary system. You rarely see three. The reason is simple: three is unstable. Consider a system with three parties trying to get their candidates elected in a winner takes all vote. If two parties have some similarities, they will tend to distribute their vote between two candidates. This weakens both candidates and causes the third party to win the seat. The only possible solution to this is for one of those two parties to "join" the other, creating a two party system. Two parties appears to be the most stable structure for a winner-takes-all parliamentary election.

As you climb above three parties, this issue becomes less of an issue because the voter base becomes so diverse. It increases the likelihood that everyone will find some common ground, so it becomes more likely that everyone has to deal with votes being "stolen" from them.

I think it's also worth mentioning a "definition" I've seen for politics, which requires three people: two people arguing trying to convince a third person to take their side.

Answer 6

I think this is a take on the 3-Body problem.

One party is aligned with their own interests, unless they are completely crazy or incompetent.

Two parties can have an alliance when they have mutual interests, or make a tit-for-tat agreement. The interests are aligned A to B and B to A. If B does something A doesn't like, then the deal is off, simple as that.

But the relationships between 3 parties are actually 6 ( A to B, B to A, A to C, C to A, C to B, and B to C ), and if any one of those interests become misaligned (e.g. that A does something C doesn't like), then that in turn screws up the rest of arrangement (C retaliates on B, to try to pressure them to lean on A). More opportunity for things to go wrong.

So why 3? Why not 4 or more? Because more parties mean even more relationships, and by the time you're at four that's already to complex a political deal for it to ever come into existence in the first place.

Answer 7

When you have 3 factions, opposing each other, it is very likely that two of them are not as different as the third. Very soon, the first two factions would form a temprorary alliance upon the common cause: to smash the third faction.
The computer game between three teams usually ends like this: two teams destroy the third and come to a standoff. That is why modern computer games tend to have either 2 or a lot of teams in one game.

Answer 8

One issue is that although a triumvirate can be stable one party shifting allegiances can cause the whole thing to collapse which creates uncertainty.

If you have two factions there is less uncertainty as they can be presumed to know each others relative strengths and weaknesses and unless there is some seismic change you can expect some sort of equilibrium to be reached. There are really only two possible situations at one time either they cooperate or the conflict.

In a three way system there are more possible permutations. For example if you have a situation where A and B are cooperating to resist C this isn't a very stable situation as you have to assume that A and B have some conflicting interests and there is always the possibility that C will make either of them a better offer.

There is also the fact that if no one side has overall control it becomes very hard to get anything done as any decision needs three way horse-trading to reach some sort of deal and the smaller faction will constantly be trying to use their leverage to get what they want.

They key thing here is the uncertainty, the balance of power can shift very quickly if one side changes their position.