The Laws of
Game Theory

The Law of the Vacuum

Why do empires form even when nobody sets out to build one? Empires are not built by choice — they emerge from the structural logic of power vacuums. Nobody has to intend it; a vacuum is filled by whoever is adjacent, capable and already armed.

The mechanism

When a dominant power withdraws from a region, it does not leave a stable absence. It leaves a set of unresolved disputes that were previously suppressed, and a set of local actors who now face a security problem they did not have to solve before.

Three conditions decide who fills the space: adjacency, because reach decays with distance; capability, meaning forces that already exist rather than forces that could be raised; and prior armament, because the window closes faster than a state can rearm.

Whoever has all three acquires responsibilities it did not seek. It intervenes once to prevent a hostile outcome, then finds that the intervention created a dependency, then finds the dependency requires protection. Each step is defensive and the cumulative shape is imperial.

That is why so many empires describe themselves accurately as reluctant. The description is often sincere and the structure does not care.

A worked example

Model any regional withdrawal as a sequence rather than an event.

Before: disputes are suppressed by an external guarantor and local actors under-invest in their own security because they do not need it.

At withdrawal: every local actor recalculates simultaneously. The question is not who wants influence but who can act within months — which eliminates everyone whose capability is theoretical.

After: the actor that acts first to prevent an unacceptable outcome acquires a client. The client's neighbours respond. The first actor now has a second problem created by solving the first.

Run that forward three iterations and you have a regional hegemon with a set of commitments none of which were chosen at the outset.

What would prove this wrong

A significant power vacuum that persists for a generation without any adjacent, capable and armed actor expanding into it — or an expansion that demonstrably began with an imperial design rather than with a defensive response.

Where it comes from

Book One, chapter Game Theory #16: Pax Judaica Rising. The law is named in the second edition of that volume.

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Last reviewed 31 July 2026