This study explores how trust arises among policy elites engaged in prolonged face-to-face negotiations. Mirroring recent evidence that citizens' procedural preferences (as opposed to policy preferences) drive trust in government, we find that interpersonal trust among stakeholders in consensus-seeking partnerships is explained by the perceived legitimacy and fairness of the negotiation process more so than by the partnership's track record of producing mutually agreeable policies. Overall, hypotheses derived from social psychology do as well or better than those based on rational-choice assumptions. Important predictors of trust include small and stable groups, generalized social trust, clear decision rules, political stalemate, congruence on policy-related beliefs, and absence of devil-shift (the belief that one's opponents wield more power than one's allies). Surprisingly, null or negative correlations exist between trust and network density, measured by membership in voluntary associations. The study illustrates the value of behavioral models that integrate institutional, rational, and psychological explanations.