This need for promises is more than incidental; it has an institutional importance of its own. It is not always easy to make a convincing, self-binding, promise. Both the kidnapper who would like to release his prisoner, and the prisoner, may search desperately for a way to commit the latter against informing on his captor, without finding one. … If the law will not enforce price agreements; or if the union is unable to obligate itself to a no-strike pledge; or if a contractor has no assets to pay damages if he loses a suit, and the law will not imprison debtors; or if there is no “audience” to which one can pledge his reputation; it may not be possible to strike a bargain, or at least the same bargain that would otherwise be struck.

XREF: Relates to Thomas Schelling's work on commitment devices and the economics of credible commitments.

Thomas C. Schelling, The Strategy of Conflict, loc. 115