The World Trade Organization (WTO) lacks the power to directly enforce agreements. It is therefore important to understand what role the WTO can play to facilitate international cooperation, and whether a multilateral institution can offer distinct advantages over a web of bilateral agreements. This paper examines two potential benefits of a multilateral trade institution: first, verifying violations of the agreements and informing third parties, thus facilitating multilateral reputation mechanisms; second, promoting multilateral trade negotiations rather than a web of bilateral negotiations. The model suggests that a multilateral approach is particularly important when there are strong imbalances in bilateral trading relationships. (JEL F13)