Law 15 closes its main body with a quotation from Machiavelli, printed as the chapter's Authority:
"For it must be noted, that men must either be caressed or else annihilated; they will revenge themselves for small injuries, but cannot do so for great ones; the injury therefore that we do to a man must be such that we need not fear his vengeance."1
Read the first six words again. Either caressed or else annihilated.
The chapter that quotation closes has spent four pages arguing for one of those two branches and treating the other as the error being warned against. Greene selects as his final authority a maxim that names an option his own text does not entertain.
The structure of Machiavelli's sentence is not be ruthless. It is a rule with three regions, and the prohibition is on the region in the middle.
Caress. Do the man no injury at all. Nothing to revenge.
Annihilate. Do him an injury he cannot revenge.
The middle. A small injury — enough to give him a grievance, not enough to disable him. This is the forbidden region, and it is forbidden not because it is weak but because it is the only one that generates a live enemy.
So the maxim is symmetric. Both endpoints are safe and the middle is fatal. Greene's chapter reads it as though only one endpoint existed, and his own summary — "never go halfway"2 — collapses a two-tailed rule into a one-tailed instruction.
The maxim's second half supplies something Law 15 badly needs and never provides: a threshold.
"The injury therefore that we do to a man must be such that we need not fear his vengeance."
That is a checkable standard, and it is relative rather than absolute. It does not say destroy him totally. It says the injury must exceed his capacity to repay it — which means the required magnitude depends entirely on the other party's remaining capability, not on some fixed idea of completeness.
Against a man with no allies and no position, a small injury may already satisfy it. Against Mao with ten thousand soldiers and a countryside, nothing short of destruction does.
Greene's law has no such variable. Crush your enemy totally is stated without reference to who the enemy is, which is why the chapter cannot say whether Chiang's 87% was nearly enough or nowhere near. Machiavelli's version can: it was not enough, because Mao retained the capacity for vengeance, and that is a fact about Mao rather than a fact about percentages.
Apply the two-branch rule to Law 15's own cases and it sorts them better than the law does.
Hsiang Yu lived permanently in the forbidden middle. He attempted the annihilation branch at the banquet, failed, and thereafter did neither — he neither caressed Liu Pang nor removed him, across four opportunities. On the maxim's terms his error is not insufficient ruthlessness. It is having taken up a position that the rule specifically prohibits, and having stayed there.
Empress Wu ran the annihilation branch to completion, and the maxim's threshold was met in every case: none of her rivals retained any capacity for vengeance.
Camillus, from Law 12, is the caress branch and Greene never connects him to this maxim. He returned the Faliscan children rather than taking them hostage, did the enemy no injury at all, and the city surrendered.3 By Machiavelli's rule that is a correct move, fully sanctioned, and it appears three laws earlier under a different heading with no cross-reference.
Chiang Kai-shek is the case the maxim explains and the law does not. He landed in the middle by circumstance rather than by sentiment, and the maxim tells you why 87% was a failure while offering no support for the claim that stopping was inherently wrong — it was wrong given what Mao retained.
Three of four cases sort more cleanly under a sentence Greene quotes and does not use.
Worth being precise about what happens to the missing option, because it is not simply ignored.
Greene's chapter has a category for treating an enemy well, and it is the failure mode: pity, sympathy, hope of reconciliation, "we nurture these resentful vipers."4 Every instance of gentleness in Law 15 is an incomplete annihilation — a stopped process rather than a chosen strategy.
Machiavelli's caress is not that. It is a deliberate, complete choice to inflict no injury, made in full possession of the ability to inflict one. Hsiang Yu did not caress Liu Pang; he tried to kill him and stopped. Camillus caressed the Faliscans.
The chapter has no vocabulary for the difference between mercy that is a completed decision and mercy that is an abandoned attempt — and that distinction is the whole of the maxim's first branch. Without it, the caress option is not rejected on the merits. It is simply unavailable to be considered.
You are about to do something to someone that will make an enemy of them.
Before you do, run the maxim rather than the law, because it asks a better question. Not how far should I go but which of two positions am I taking.
Position one: do nothing to them at all. Not out of weakness — out of a decision that the injury is not worth the enemy. This is a real option and it has to be taken deliberately, in full, and be visible as a choice rather than as a failure of nerve. Camillus gave the children back and the city opened.
Position two: make the injury exceed their capacity to repay it. And now the useful part — that magnitude is not a fixed quantity. It is set by them, not by you. So the actual work is an inventory of what they will still have afterwards: the relationships, the standing, the people who will take their call, the story they will be able to tell. If any of that remains sufficient to hurt you, the injury has not met the threshold, and going harder is not necessarily the answer — the answer might be that this injury cannot be made safe and therefore should not be inflicted.
And the position to avoid is the one that feels most reasonable in the moment. A partial measure. A demotion rather than a removal. A pointed comment rather than a case made properly. It reads as proportionate and restrained, and it is the only one of the three positions the maxim actually forbids.
The strongest thing about this passage is that it is a rule rather than an exhortation — two branches, a forbidden middle, and a relative threshold. Nothing else in Law 15 has that structure, which is why it sorts the chapter's cases better than the chapter does.
Tension: the Authority contradicts the law it authorises. Greene selects a maxim that endorses a branch his chapter treats as the error, and quotes it approvingly at the end. Documented, not resolved.
Tension: the threshold is relative and the law is absolute. Machiavelli's magnitude is set by the enemy's remaining capacity; Greene's is set at total. These give different answers in every case where the enemy is weak, and the chapter contains no such case.
Tension: Camillus. The caress branch has a working example in this book, three laws earlier, and Greene neither cross-references it nor treats it as an instance of anything general.
🚩 SECONDARY WITHOUT PRIMARY — the Machiavelli passage is given with dates (1469–1527) and no work, chapter or translator. It corresponds closely to material in The Prince, but the chapter provides no way to check it, and the surrounding argument in the original is not available from this source. [POPULAR SOURCE] · [PLAUSIBLE — needs corroboration]
Open questions. Does the caress branch require the ability to annihilate in order to work — is Camillus's refusal persuasive only because everyone knew he could have taken the hostages? And if the threshold is relative to the enemy's remaining capacity, what does the rule say to someone whose adversary is stronger than they are, which is the position the maxim never addresses and most readers occupy?
Within Law 15 this is the second Authority-versus-body-text conflict logged in Cluster E, after Law 14's Sun-tzu passage disqualifying Greene's own method of argument. Sixth instance in the build of a marginal or Authority quotation supplying something the body lacks — here, the criterion the chapter is missing.
Against the vault's Siu material, the maxim splits the difference the two writers cannot. Siu's Law of Reversal warns that approaching total dominance summons countervailing power; Greene warns that stopping short leaves a live enemy. Machiavelli's rule is compatible with both, because its threshold is the enemy's capacity for vengeance rather than completeness. An injury calibrated to that threshold can be far short of annihilation, which is exactly the region Siu is protecting and Greene has no name for.
And the caress branch answers the Versailles objection that Law 15's own Reversal could not. The Reversal raises Versailles, concedes the point, and replies simply crush them again. The maxim's answer is available and better: Versailles was the forbidden middle — an injury large enough to guarantee vengeance and not large enough to prevent it. That reading requires no counter-evidence and no repetition, and Greene printed the sentence that supplies it twelve lines earlier.
Psychology — Loss Aversion and Asymmetric Valuation
Losses loom larger than equivalent gains — the same quantity hurts more leaving than it pleases arriving, by a consistent factor.
That is the mechanism under the forbidden middle, and it explains why the middle is worse than either end rather than intermediate between them.
A small injury is small to the person inflicting it and is evaluated by them as a small quantity of harm. To the person receiving it, the identical quantity sits on the steep side of the value function and registers as considerably larger. So a partial measure is systematically mispriced by the only person deciding whether to take it — it looks proportionate from one chair and disproportionate from the other, and both readings are sincere.
The insight neither has alone: this predicts that the forbidden middle is not an occasional error but the default one. Anyone calibrating an injury by how large it feels to inflict will land there, reliably, because their own valuation of the harm is the wrong instrument. Machiavelli's rule is unusual precisely because it refuses that instrument and measures against the target's remaining capacity instead — an external quantity that does not deform with which side of it you are standing on. Which reframes the maxim as a debiasing device rather than a piece of ruthlessness.
Business — The Monopoly Trap
Greene's own Law 11 Reversal, as that page reports it: the monopolistic escalation has three failure modes, and coalition is the strongest, because it manufactures opposition — the monopolist gives scattered, mutually hostile parties the one thing they have in common.
Set that against the annihilation branch and the maxim acquires a limit it does not state.
Machiavelli's threshold is calculated against one enemy's capacity for vengeance. It is a two-party rule. The monopoly page's finding is that a sufficiently complete injury to one party changes the standing of everyone watching — it converts observers into a class with a shared interest, and the resulting coalition's capacity for vengeance was never in the original calculation.
What the pair produces: the maxim is sound for a single adversary and systematically underestimates the required magnitude in any environment with an audience — because the enemy whose capacity you must exceed is not the one in front of you but the one your action creates. That is why Empress Wu's sealed court satisfied the rule and Versailles did not, despite Versailles being by far the larger injury. The variable is not how hard you hit. It is how many people can see themselves in the position of the person you hit, and neither Machiavelli nor Greene has a term for it.
Sharpest implication. The rule that should govern Law 15 is printed at the end of Law 15 and is not the law. Two safe positions and one forbidden region between them, with the region defined by the target's remaining capacity rather than by the actor's sense of proportion — which means the reliable error is not insufficient ruthlessness but calibrating from the wrong chair.
Generative questions.