The Laws of
Game Theory

The Law of the Useful Enemy

When are two opposing systems actually working together? Two systems presented as opposites are frequently allied in effect, because each dissolves the obstacles the other cannot reach. The test is not what either says but what is left standing when both have done their work.

The mechanism

Ideologies are usually read by their stated aims. Read them instead by what they demolish, and pairs that appear to be at war often turn out to be clearing complementary ground.

The mechanism does not require coordination. A movement that attacks inherited authority and a movement that attacks collective obligation may despise each other sincerely while jointly removing every institution capable of constraining a third party. Neither intends the outcome; both produce it.

The analytical move is to stop asking who wins the argument and start asking what survives it. List the powers that existed before the conflict, and mark which ones each side has weakened. Where the two lists complete each other, and where the remaining power is one neither side targeted, you have this law.

It is a structural claim, not an accusation of conspiracy. Selection over decades does this work without anyone planning it.

A worked example

Take any long ideological contest and draw three columns.

First column: the institutions that existed before it began — inherited authority, religious institutions, local associations, guilds, extended family obligation, national loyalty.

Second column: which of those the first side attacked and weakened. Third: which the second side attacked and weakened.

Now look at what has no mark in either column. If a particular form of power was targeted by neither side and is stronger at the end than at the beginning, that is the finding. The contest was real, the hostility was sincere, and the joint effect was to remove everything that constrained the survivor.

What would prove this wrong

A long ideological contest in which the surviving powers are the ones both sides explicitly targeted, or in which the institutions weakened do not complement each other in any coherent way.

Where it comes from

Book One, chapter Game Theory #8: Communist Specter. The law is named in the second edition of that volume.

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Last reviewed 31 July 2026