Also, the pure games cannot admit “side payments.” If one of the partners in a pure common-interest game threatens to sabotage the effect unless he is paid—assuming that the communication and enforcement structure of the game makes this possible—a conflict of interest is introduced; in effect, the point denoting the payment of a bribe would appear to the upper left or lower right of another point or points on the upward-sloping line, producing the configuration of a mixed game. And if one of the players in a pure-conflict game can threaten damage or offer compensation to induce his opponent to yield in this game, there is scope for bargaining; there is no longer a relation of pure conflict, and the points denoting the threatened damage or promised compensation would lie off the downward-sloping line. In other words, all pertinent potential outcomes must be allowed for.

DEFINE: Explains how introducing side payments (bribes or compensation) shifts a pure common-interest or pure-conflict game into a mixed game configuration, redefining the game's structural category.

Thomas C. Schelling, The Strategy of Conflict, loc. 737