The Uruguay Round Agreement made significant changes to the governance of international trade. Trade rules and dispute settlement mechanisms were altered and a series of specific agreements provided for liberalisation across economic sectors. The Agreement on Agriculture, arguably the most difficult and contentious to negotiate, permitted the continued use of trade-distorting instruments, both domestically and at the border. Rule-enforcement in agriculture therefore relies crucially on the clarity of the rules. This paper provides an in-depth study of a unique and critical case for understanding the new rules: the EC sugar regime. This policy was challenged unsuccessfully under the pre-Uruguay Round rules, but successfully under the new rules. This case is particularly valuable in allowing us to isolate the effect of the Uruguay Round on agricultural trade disputes: the policy under challenge was essentially unchanged and the legal actions addressed the same concern - excessive export subsidisation. Drawing on primary and secondary materials and interviews with key policy actors, sugar is used to illustrate how those involved in the multilateral process learned from particular rule weaknesses revealed in earlier cases, revising those rules in the Uruguay Round in such a way that dispute panels can more readily and objectively determine rule breaches.