Future interaction benefits enforce present trustworthiness. [causal]
The incentive to cooperate (or to fulfill a trust) and the sanction not to do so are one and the same. They are the benefits of future interaction that ride on present trustworthiness.
DEFINE: Clarifies that cooperation incentives and sanctions are the same thing — the value of future interactions contingent on being trustworthy now.
Russell Hardin, Trust and Trustworthiness, loc. 593