Adversaries may gain by buying each other’s defensive capacity

Evidence

If R can, at his own expense, improve his “enemy’s” alert system, or if he can blunt his own surprise capacity in a visible way, to hold Qr below the limit, he should do so. The principle is the same as that of two partners, somewhat distrustful, who keep two separate private padlocks on the partnership vault. If one could not afford a padlock, the other should provide it to him at his own expense; only then can they do business together. — Thomas C. Schelling, The Strategy of Conflict, 818

Categorization

• XREF: Funder one’s own enemy’s defense parallels the Mafia investing in credible mechanisms that reassure rather than threaten the other party — a tie-in to the reader’s private-enforcement model. — connects to: Rational self-defense adjustments are compatible with both sides still preferring mutual non-attack — Thomas C. Schelling, The Strategy of Conflict, 504; Both rivals seek a detection advantage while hoping none is found — Thomas C. Schelling, The Strategy of Conflict, 543

Related

• Both rivals seek a detection advantage while hoping none is found (similarity 0.78)