Modem international organisations are complex, multi-faceted institutions that are I As a corol transforming the way in which States comply with international rules. lary of that transformation independent action by individual states is under pres sure from other states in a range of cooperative regimes that make up modem international society.2 The World Trade Organization (WTO)3 exemplifies this trans formation. It has emerged from its former institutional framework of the General Agreement on Tariffs and Trade (GATT) into a fully-fledged international economic 4 organisation, with a specific mechanism for the settlement of disputes and a strong ethos of enforcement. Notwithstanding such developments, there is no satisfactory theory to explain what determines a compliance decision in WTO law or to account for the fact that 5 Instead, there is a general assumption that some Members choose not to comply. WTO Members are in compliance with their obligations and, more particularly with decisions which have been adopted by the Dispute Settlement Body. The issue of compliance with multilateral treaty regimes has been of consider able interest to political scientists and has spurned a burgeoning literature at the 6 intersection of international relations and international law, often arising from enquiries into the effectiveness of international regimes. In the context ofmultilat 7 eral treaty regimes two different perspectives on compliance have emerged in the 1. J.E. Alvarez, International Organizations as Law-makers (Oxford, Oxford University Press 2005) pp. ix-xxi at xv.