736 International Organization been easier for the United States to pursue remedies at NAFTA.Why,then,did Mexico and the United States defy expectations in choosing where to litigate these cases?More generally,how do members select among overlapping institutions in deciding which (if any)to petition in trying to resolve their conflicts?This prac- tice,which legal scholars call forum shopping,is a key part of any litigation strat- egy but has received little attention in international relations.3 This article advances a theory of forum shopping for dispute settlement in international trade. I argue that a complainant's choice of forum depends on whether it prefers to set a regional or multilateral precedent,or no precedent at all.Setting precedent means adding to an institution's body of case law concerning the obligation(s)in dispute.The incentive for a complainant to do this is that,in addition to curbing the defendant's protectionism,a precedent can facilitate future litigation,and encour- age more ex ante settlement,in relations with other members of the same institu- tion.The complainant must therefore be strategic about where it sets a precedent: while new case law can be used in litigation against other trade partners,it can also be used by these other trade partners to bring suits against the complainant. Forum shopping is thus about discriminating among overlapping memberships:a complainant may prefer that some precedents pertain only to members of a regional institution,others to members of the multilateral institution,and at times prefer not to set a precedent at all. Using a two-dimensional spatial model,I show that this decision depends on two variables:(1)the complainant's preference concerning the outcome of the dis- pute,which I define as being more or less "liberal,"or free-trade oriented,than the status quo policies of the defendant,other trade partners,and the likely ver- dicts of the regional and multilateral institutions;and(2)the complainant's expec- tation concerning the future value of the precedent set,by which I mean the likelihood that the complainant will use the resulting case law in future litigation against other members,more than other members will use it against the complain- ant.These variables combine to show that the complainant choice of forum is not simply a function of which institution is likely to come the closest to its ideal ruling against the defendant,but where the resulting precedent will be more use- ful,facilitating litigation against other members,as opposed to inviting litigation against itself.In particular,an illiberal complainant is more likely to file region- ally,and a liberal one multilaterally,even if they expect a more decisive legal victory over the defendant at the other institution.Yet,both will reverse their choice of forum if the expected value of future regional litigation is higher,an illiberal 3.Black's Law Dictionary defines forum shopping as "when a party attempts to have his action tried in a particular court or jurisdiction where he feels he will receive the most favorable judgment or verdict."The importance of forum shopping in domestic litigation is discussed in Clermont and Eisen- berg 1995,while its importance in Canada-U.S.trade is discussed in Howse 1998. 4.Setting a precedent can encourage subsequent disputes to end in a negotiated settlement before the panel rules,or deter protectionist practices from arising in the first place.In other words,there is nothing about this argument that suggests that all later disputes will necessarily result in a legal verdict.been easier for the United States to pursue remedies at NAFTA+ Why, then, did Mexico and the United States defy expectations in choosing where to litigate these cases? More generally, how do members select among overlapping institutions in deciding which ~if any! to petition in trying to resolve their conflicts? This prac￾tice, which legal scholars call forum shopping, is a key part of any litigation strat￾egy but has received little attention in international relations+ 3 This article advances a theory of forum shopping for dispute settlement in international trade+ I argue that a complainant’s choice of forum depends on whether it prefers to set a regional or multilateral precedent, or no precedent at all+ Setting precedent means adding to an institution’s body of case law concerning the obligation~s! in dispute+ The incentive for a complainant to do this is that, in addition to curbing the defendant’s protectionism, a precedent can facilitate future litigation, and encour￾age more ex ante settlement, 4 in relations with other members of the same institu￾tion+ The complainant must therefore be strategic about where it sets a precedent: while new case law can be used in litigation against other trade partners, it can also be used by these other trade partners to bring suits against the complainant+ Forum shopping is thus about discriminating among overlapping memberships: a complainant may prefer that some precedents pertain only to members of a regional institution, others to members of the multilateral institution, and at times prefer not to set a precedent at all+ Using a two-dimensional spatial model, I show that this decision depends on two variables: ~1! the complainant’s preference concerning the outcome of the dis￾pute, which I define as being more or less “liberal,” or free-trade oriented, than the status quo policies of the defendant, other trade partners, and the likely ver￾dicts of the regional and multilateral institutions; and ~2! the complainant’s expec￾tation concerning the future value of the precedent set, by which I mean the likelihood that the complainant will use the resulting case law in future litigation against other members, more than other members will use it against the complain￾ant+ These variables combine to show that the complainant choice of forum is not simply a function of which institution is likely to come the closest to its ideal ruling against the defendant, but where the resulting precedent will be more use￾ful, facilitating litigation against other members, as opposed to inviting litigation against itself+ In particular, an illiberal complainant is more likely to file region￾ally, and a liberal one multilaterally, even if they expect a more decisive legal victory over the defendant at the other institution+ Yet, both will reverse their choice of forum if the expected value of future regional litigation is higher, an illiberal 3+ Black’s Law Dictionary defines forum shopping as “when a party attempts to have his action tried in a particular court or jurisdiction where he feels he will receive the most favorable judgment or verdict+” The importance of forum shopping in domestic litigation is discussed in Clermont and Eisen￾berg 1995, while its importance in Canada–U+S+ trade is discussed in Howse 1998+ 4+ Setting a precedent can encourage subsequent disputes to end in a negotiated settlement before the panel rules, or deter protectionist practices from arising in the first place+ In other words, there is nothing about this argument that suggests that all later disputes will necessarily result in a legal verdict+ 736 International Organization