A body has a problem that it solves efficiently and dangerously: it moves almost everything through a small number of narrow vessels. It works, right up until it does not — and the failure is never local.
World trade has the same problem, and for the same reason: concentration is efficient.
The Silk Road was never a road
The original Silk Road was not a highway between two empires. It was a set of corridors through which goods moved between civilisations that had almost no contact otherwise — and what travelled fastest along them was not silk but technique, mathematics, medicine and religion.
Its importance was never the distance. It was the contact density it created along the way: the cities that existed because they sat on one of those corridors, and the exchange that happened in them.
“Silk Road 2.0” is the observation that the same structure has returned at much larger scale. A handful of maritime and terrestrial corridors carry a disproportionate share of everything, and within them, a few narrow points can stop the flow entirely.
Three things follow from treating trade as circulation
Concentration is efficient, so it is self-reinforcing. Scale economies mean the cheapest route gets the volume, which means it gets cheaper, which means it gets the volume. You cannot disperse this by declaring it undesirable; you can only pay for the redundancy you want.
Redundancy is a public good, so it is underprovided. Everyone benefits from a bypass; nobody profits from building one. This is exactly why the world’s arteries are narrower than its risk appetite.
Using a chokepoint as a weapon destroys it as a weapon. This is the interesting one, and it is arithmetic rather than morality. The value of a chokepoint is that everyone must use it. Every blockade — even a short-lived one — gives every user a reason to build the alternative that makes them not have to. It is a wasting asset: the moment you spend it, it is worth less.
Hormuz, as the worked case
The Strait of Hormuz is the clearest instance because its parameters are extreme: roughly a fifth of global petroleum liquids passes through it, and the bypass pipelines carry a small fraction of that volume.
So any realistic closure removes a large share of capacity at once. Energy prices are set at the margin, so the cost is not borne proportionally — a small physical deficit produces a large price effect, immediately, for everyone.
That is the cost to users. The cost to the blocker is the part nobody counts: enforcement deployed continuously, retaliation available to many parties, and — the durable one — every importer’s response is to accelerate diversification, which is precisely the destruction of the leverage they just used.
And here is where the model must be honest about itself. Hormuz is a positional good. Controlling it is worth an enormous amount, which is exactly why it generates conflict rather than trade. The model says blocking is self-harming for a party whose interest is production. It does not say no one will ever find blocking rational, because a party may value position over production. Confusing the two is how a theory becomes a slogan.
The four limits of the analogy
A metaphor that is not bounded stops being thinking and becomes decoration. This one has four hard limits:
Arteries have no agency; trade does. A blocked artery cannot reroute. Trade can, given time — so the model overstates the short-run cost and understates the adaptation. That adaptation is exactly what destroys the chokepoint’s value, so the model is right about the direction and wrong about the speed.
Arteries have no alternatives; trade does. Bypasses exist, cost more, and get built when risk justifies them. Over time the cost of an occlusion falls towards the cost of the redundant capacity, not the cost of the blockage.
“The health of the planet” is figurative. The planet is not an organism and does not sicken. What is real is that many small blockages add up to a large aggregate loss that nobody individually bears — a collective-action problem, not a medical one. Calling it health is useful shorthand and a dangerous literal.
The model says nothing about distribution. An aggregate loss can coexist with a large individual gain. Any claim that “blocking hurts everyone” must immediately add that it can still be rational for someone — which is why the argument for open corridors cannot rest on arithmetic alone.
Why this matters beyond shipping
The same logic that makes a body fragile makes a company fragile, and a supply chain, and a technology stack: efficiency concentrates, concentration concentrates risk, and the redundancy you did not pay for is the redundancy you will wish you had. That is the whole of the NEPTUNO argument about resilience, applied to geography instead of to infrastructure — and it is offered as an analogy here, not as evidence, because a company framework proves nothing about geopolitics.
The paper sets out the model, the cost equation, the Hormuz case and a list of four ways the theory could be wrong. That last part is the point. A theory that cannot say what would refute it is not a theory.
The claim, at the strength it can hold: trade concentrates in narrow corridors; concentration is efficient and therefore durable; the efficient level of concentration is above the safe level; and for any actor whose interest is production rather than position, the arithmetic of a blockade is negative — including for the actor who imposes it.
It is a theory. It has a model, a case, and a list of ways to prove it wrong.
Formal version: WP 18 — Arteries of the Earth: Chokepoints, Trade Circulation and Why Blocking Them Is Self-Harming
This is the readable version. The paper builds the circulation model, works the Hormuz case, derives the occlusion cost equation, and lists four ways the analogy fails — including that it cannot carry the claim that blocking is never rational.