There is an ongoing debate about best ways to assess the compatibility of RTAs with WTO rules and the possible negative impact that the proliferation of RTA formation may have on individual members and on the stability of the multilateral trading system as a whole. Therefore, rules defining the WTO compatibility of RTAs are one of the issues under in the WTO Doha negotiations. Taking the current EPA negotiations between ACP and EU as an example, this paper examines two sorts of questions: (i) the implications for developing country members of the current proposals to tighten the rules on WTO compatibility of RTAs; (ii) the impact that the proliferation of RTA formation may have on non-RTA members and on the stability of the multilateral trading system as a whole. More specifically, the paper assesses quantitatively using a partial equilibrium framework the implications for ACP countries of some of the proposals to reform GATT Art. XXIV, in particular the “substantially all trade” criteria. Based on a CGE approach, the paper then looks at the implications of EPA negotiations on third countries and its linkages with the ongoing Doha negotiations, in particular on how the future EPA agreements could be non-trade diverting, in line with Ohyama-Panagariya-Krishna version of the Kemp-Wan theorem
