III.4.1 Consultations

Consultations are confidential (articles 4.6 DSU, 17.5.8 PA-AP and 28.5.8 TPP) and start with a written request that shall include the identification of the measure and the legal basis for the complaint (articles 4.4 DSU, 17.5.1 PA-AP and 28.5.1 TPP). Deadlines for consultations are similar, yet slightly shorter in the CPTPP, and parties may agree to modify them (articles 4.3 DSU, 17.5.4 PA-AP and 28.5.2 TPP). Timeframes for consultations are shorter for urgent cases, such as when perishable goods are involved (articles 4.8 DSU, 17.5.5 PA-AP and 28.5.4 TPP).

As mentioned above, the scope of application of the PA-AP and the CPTPP includes planned measures. Consequently, parties to the PA and the CPTPP-unlike the WTO- may request consultations with respect to planned measures (articles 17.5.1 and 17.3 PA-AP, and 28.5.1 and 28.3 TPP). In contrast to the DSU, consultations may be held in person or by any technological means (articles 17.5.9 PA-AP and 28.5.5 TPP).

III.4.2 Post-consultation phase

PA-AP dispute settlement is unique in including a post-consultation phase. The FTC assists parties to settle their dispute, by means of convening technical advisers or working groups, recurring to alternative dispute settlement mechanisms, and even making recommendations (article 17.6 PA-AP).

III.4.3 Panel or arbitrator

The three dispute settlement systems include a panel or arbitration phase.

III.4.3.1 Establishment of a panel or arbitrator

A party that requested consultations may request the establishment of a panel (articles 6 DSU and 28.7 TPP) or arbitrator (article 17.7 PA-AP). The requesting party has to identify the measure or matter at issue and the legal basis of the complaint. In the WTO, it is the DSB who decides to establish (or not) the panel.

As already highlighted, PA-AP and CPTPP dispute settlement systems apply to planned measures, whereas the DSU does not. However, PA-AP arbitrators and CPTPP panels shall not be established to review proposed measures (articles PA-AP 17.7.3 and 28.7.7 TPP); thus, only consultations are available. By contrast, planned measures may arguably be framed as situation complaints pursuant to article 26.2 DSU, whereas the PA-AP and CPTPP do not allow situation complaints. Thus, at first glance it may seem that the PA-AP and CPTPP are more amenable to reviewing planned measures, but actually it is the WTO dispute settlement system.

Parties may agree on the terms of reference. If they fail to do so, standard terms of reference apply (articles 7 DSU, 17.11 PA-AP and 28.8 TPP).

III.4.3.2 Composition and selection of the panel or arbitration tribunal

The composition of panels or arbitration tribunal is similar, but selection processes differ widely, from the relatively simple (articles 8 DSU, 17.12 and 17.13 PA-AP) to the complex (article 28.9 TPP).

The WTO Secretariat maintains an indicative list of candidates (article 8 DSU). Panelists, as a general rule, should not be citizens of parties to the dispute. Parties to the dispute can only oppose that nomination for compelling reasons. In case of disagreement, the WTO Director General determines the composition of the panel in consultation with certain chairpersons. The selection of panelists should ensure the panel’s independence.

Article 17.13 PA-AP provides that each party to the dispute designates one arbitrator, who can be a national of that country. If a party fails to appoint an arbitrator, the other party may designate the missing arbitrator from the WTO indicative list of candidates. The parties to the dispute then select a president, who shall not be a national of any party nor permanently reside in a party. If they fail to choose a president, the PA pro tempore presidency will select by lot.

Blocking the panel selection process had been singled out as “a fundamental flaw” in dispute settlement pursuant to the North American Free Trade Agreement (NAFTA), especially since the dispute about restrictions on sugar from Mexico (Lester, Manak, & Arpas, Access to Trade Justice: Fixing NAFTA's Flawed State-to-State Dispute Settlement Process, 2019, pp. 64-69). Chapter 28 TPP corrects some shortcomings of NAFTA dispute settlement, especially to avoid the deadlocks under the NAFTA process regarding the selection of panel members (^{Toohey, 2017}, pp. 94, 99). Pursuant to article 28.9.2 TPP, each party to the dispute shall appoint one panelist within a certain timeframe. If the complaining party fails to do so, the proceeding lapses. If the responding party fails to appoint a panelist, the complaining party shall select a panelist from the responding party’s roster list. If the responding party has not established a roster list, the complaining party nominates three candidates and the panelist is randomly selected. Parties to the dispute appoint the panel chair who, as a general rule, shall not be a national of any of the disputing or third parties. If they do not agree on the chair, the two appointed panelists shall designate the chair from the roster list. If the two panelists do not agree on the chair, they shall appoint with the agreement of the parties to the dispute, or the parties shall appoint the chair by random selection from the roster list, or a party may request an independent third party to select the chair from the same roster. If the roster list has not been established, the parties to the dispute may nominate three candidates and the chair will be selected randomly or by an independent third party.

III.4.3.3. Rules of procedure

In the three systems, parties to the dispute may modify the rules of procedure (articles 12.1 DSU, 17.14.2 PA-AP and 28.12.2 TPP).

The DSU itself only schematically refers to rules of procedure and leaves the rest for the panel to decide. Rules should aim for flexible and efficient procedures, and high-quality reports, while providing parties sufficient time to prepare their submissions (article 12.2 and 12.4 DSU). There are specific rules of procedure for disputes that involve developing countries (article 12.10 and 12.11 DSU).

Articles 17.14 PA-AP and 28.13 TPP provide that the PA FTC and the TPPC shall establish rules of procedure. Those rules must include at least one public hearing and an initial and a rebuttal written submission. They must protect confidential information. PA-AP arbitrators’ deliberations are confidential (article 17.14.3 (e)) in contrast to the CPTPP. CPTPP rules of procedure shall allow amicus curiae briefs and specify the place where hearings shall be held (article 28.13 (e) and (h)) contrary to the PA-AP. Pursuant to articles 17.14.7 PA-AP and 28.12.4 TPP, the panel/arbitral tribunal shall decide by consensus but, if it is unable to reach consensus, it may decide by majority vote.

PA-AP arbitrators shall, as a general rule, issue their report after 120 days, and after 180 days (or six months) for CPTPP and DSU panels. Timeframes may be shortened or extended under certain circumstances or when the parties so agree (articles 17.15 PA-AP, 3.12, 12.8 and 12.9 DSU, 28.17.3 and 28.18.1 TPP). However, dispute settlement practice in the WTO shows that such timeframes are often not met.

III.4.3.4. Reports and awards

According to article 15 DSU, the panel first issues the descriptive sections of its draft report to the disputing parties, then it issues an interim report to the parties, and finally the panel issues a final report and circulates it to WTO Members. Pursuant to article 19 DSU, if the panel concludes that a measure is inconsistent with the covered agreements, it shall recommend the Member to bring the measure into conformity with the agreement and may suggest ways to implement the recommendations (but without adding or diminishing the rights and obligations provided in the covered agreements). According to article 16, this final report shall be considered for adoption by the DSB, unless it decides by consensus not to adopt it, or a party notifies its decision to appeal.

PA-AP arbitrators issue a draft award and a final award. The draft report shall determine if the defending party has complied with its obligations, or if the measure causes nullification or impairment, and it shall include any determination requested in the terms of reference (article 17.15 PA-AP). It may include a recommendation to bring the measure into conformity with the PA-AP, and it may suggest implementation methods (article 17.15.5). Mirroring the DSU, the PA-AP arbitrator cannot add or diminish the parties’ rights and obligations (article 17.15.6). Parties may comment on the report and the arbitrator may reconsider the draft report (article 17.15.7 and 17.15.8). After 30 days, the arbitrator notifies the final award to the disputing parties. This award is definitive, unappealable and binding (article 17.16).

CPTPP panels issue an initial and a final report. Pursuant to article 28.17.4 TPP, the initial report shall include findings of fact, the determination whether the measure is inconsistent with the obligations set in the agreement, if the defending party has not otherwise failed to carry out its obligations, or if the measure causes nullification or impairment. It shall also contain determinations requested in the terms of reference and the reasons for the findings and determinations. Unlike the DSU and the PA-AP, the CPTPP provides that only if disputing parties jointly request it, the panel may make recommendations. Similarly to the PA-AP, parties may comment on the initial report and the panel may modify it (article 28.17.7 and 28.17.8). Then the panel presents a final report to the disputing parties and releases it to the public (article 28.28.1).

III.4.4. Appeals

The appeal phase is arguably the most important difference between the DSU, and the PA-AP and the CPTPP. Few RTAs include an appeal mechanism, such as article 12 ASEAN Protocol on Enhanced Dispute Settlement Mechanism and chapter VII MERCOSUR Olivos Protocol, but the PA-AP and the CPTPP do not.

According to article 17.6 DSU, appeals are limited to issues of law covered in the panel report and legal interpretations developed by the panel. The AB may uphold, modify, or reverse the panel’s legal findings or conclusions (article 17.13). Like the panel, also the AB may suggest ways in which the defending party could implement the recommendations, but without adding or diminishing the rights and obligations provided in the covered agreements (article 19). AB reports must be adopted by the DSB, unless the DSB decides by consensus not to adopt it (article 17.14).

III.4.5 Implementation and surveillance

According to article 21 DSU, if immediate compliance with recommendations or rulings of the DSB is impracticable, the defending party shall have a reasonable period of time to do so. The defending party may propose a period of time and the DSB may approve it (article 21.3 (a) DSU); since the DSB decides by consensus (article 2.4 DSU), at first glance it seems that there is multilateral control of this issue. However, if the DSB does not approve, the disputing parties may mutually agree on a period of time (article 21.3 (b) DSU); thus, the DSU considers this a strictly bilateral issue. In the absence of agreement by the parties, an arbitrator shall determine the period of time (article 21.3 (c) DSU), thus multilateralizing the issue. If the disputing parties disagree as to if the defendant has implemented the panel and/or AB report, they may recur again to the panel and AB proceedings (article 21.5 DSU). Additionally, article 21.6 DSU provides for multilateral surveillance of the implementation of adopted recommendations and rulings, as any WTO Member may raise issues of implementation at the DSB and the defending party shall submit status reports.

Implementation proceedings pursuant to article 21.5 DSU may lead to an endless loop of dispute settlement, possibly preventing the complainant from moving the dispute to the next procedural steps. This is the so-called sequencing issue and was a matter of contention especially during the WTO’s early years. Nowadays, parties to a WTO dispute often reach an agreement regarding this issue.

Pursuant to article 17.19.1 PA-AP, the disputing parties shall agree on terms of compliance consistent with the determinations, conclusions, and recommendations of the arbitrator. There are no rules regarding a period of time to comply.

Article 28.19.3 TPP states that, in general, the defendant shall comply immediately. If that is not practicable, the responding party shall have a reasonable period of time to comply, unless the parties agree otherwise. If the disputing parties do not agree on that period of time, the chair may determine the period through arbitration (article 28.19.4 TPP).

Thus, procedural rules for determining a reasonable period of time to comply differ starkly. For instance, the PA-AP and CPTPP do not consider disputes about implementation, thus avoiding the sequencing issue. More importantly, the three systems include implementation procedures that depend on the parties to the dispute; however, the DSU adds a multilateral surveillance system, whereas the PA-AP and CPTPP leave surveillance as a bilateral issue. Multilateral name-and-shame monitoring undoubtedly strengthens the WTO dispute settlement system and arguably increases legitimacy, whereas the PA-AP and the CPTPP rely more strongly on countermeasures to achieve implementation.

III.4.6 Non-implementation, compensation, and suspension of benefits

According to articles 3.7, 22.1 and 22.2 DSU, parties should first strive for a mutually acceptable solution that is consistent with the covered agreements. The second-best choice is that the defendant fully implements the panel and/or AB reports, thus withdrawing the measures found to be inconsistent with the covered agreements. Third, the defendant may voluntarily grant temporary compensation pending the withdrawal of the measure. As a last resort, the complainant may request the DSB for a temporary authorization to suspend obligations to the defendant. The level of suspension shall be equivalent to the level of nullification or impairment (article 22.4 DSU). Article 22.3 DSU contains the principles and procedures that determine which obligations to suspend. If the disputing parties do not agree on the level of suspension, the DSB shall refer the matter to arbitration (article 22.6 DSU). The DSB shall continue to keep the issue under multilateral surveillance until the defendant brings the measure into conformity with the covered agreements (article 22.8 DSU).

Pursuant to article 17.20.1 PA-AP, the preferred solution is that the parties reach an agreement on implementing the arbitrator’s report, or on a mutually satisfactory solution. If they do not, parties may agree on a temporary mutually acceptable compensation. If that fails, or if the complainant considers that the defendant has not fulfilled the agreement regarding implementation, a solution, or compensation, the complainant may suspend obligations vis-a-vis the defendant (article 17.20.2 PA-AP). The level of suspension shall be equivalent to the level of nullification or impairment (article 17.20.2 PA-AP), identically to article 22.4 DSU. The principles and procedures to determine which obligations to suspend set forth in article 17.20.4 PA-AP are very similar to article 22.3 DSU. A main procedural difference is that the complainant may start to suspend obligations at any time (article 17.20.2 PA-AP) and the defendant may only then ask for an arbitrator to prospectively review the level of suspension or to prospectively review if the defendant has complied with the arbitrator’s report (article 17.22.1, 17.22.6 and 17.22.7 PA-AP); by contrast, WTO law grants the defendant the right to recur to dispute settlement procedures on compliance (article 21.5 DSU) and to arbitration on suspension of obligations (article 22.6 DSU) before the complainant may actually start suspending obligations. Thus, the PA-AP favors the complainant, who may suspend obligations that an arbitrator may ultimately overturn, whereas the DSU favors the defendant, who may recur to articles 21.5 and 22.6 DSU to effectively delay the complainant’s countermeasures.

Pursuant to article 28.20.1 TPP, after the reasonable period of time to comply has expired (or more improbably, if the defendant notifies that it will not comply with the panel report), the complainant may request the defendant to enter into negotiations with a view to developing mutually acceptable compensation. If they do not agree on compensation, or if the complainant considers that the respondent has failed to observe the terms of the agreement, the complainant may suspend benefits (article 28.20.2 TPP). The principles and procedures to determine what benefits to suspend (article 28.20.4 TPP) follow article 22.3 DSU more closely than article 17.20.4 PA-AP, for example regarding the importance of affected trade and the broader economic circumstances and consequences.

Similarly to the PA-AP, and in contrast to the DSU, the complainant may begin suspending benefits (article 28.20.3 and 28.20.6 TPP) and only then may the defendant request the panel to be reconvened (article 28.20.5 TPP). That panel may prospectively review the level of suspended benefits, it may assess if the complainant has followed the principles and procedures to determine what benefits to suspend, or it may decide if the suspension is unjustified because the defendant has already complied with the panel report. Thus, like the PA-AP, the CPTPP favors the complainant in this regard.

As in the DSU and the PA-AP, the level of suspension is bound by a criterion of equivalence, but in the CPTPP that benchmark is different: the level of suspended concessions shall have an effect equivalent to that of the non-conformity, or nullification or impairment (article 28.20, footnote 3, TPP). Thus, the emphasis is on effects, thus necessarily calling for some sort of econometric modeling. In practice, arbitrators pursuant to article 22.6 DSU have sometimes not relied on effects, but e.g., on the value of subsidies (Brazil - Aircraft (Art. 22.6), US - FSC (Art. 22.6), Canada - Aircraft (Art. 22.6)). However, they have repeatedly applied econometric models to estimate the effects of nullification or impairment and countermeasures in terms of foregone trade flows (such as EC - Bananas III (US) (Art. 22.6), EC - Hormones (US, Canada) (Art. 22.6)), lost net transfers (US - Copyright Act (Art. 25)), economic effects (US - Upland Cotton (Art. 22.6)), etc. Put differently, the CPTPP requires the panel to consider effects, thereby excluding some approaches followed by certain WTO arbitrators, but it does not specify what kind of effects the panel should consider, hence still leaving considerable leeway.

The complainant shall postpone countermeasures if the defendant offers to pay a monetary assessment (article 28.20.7 TPP). If the parties do not reach an agreement on the amount of the assessment, it shall be set at a level equal to 50% of the level of the benefits determined by the panel or, if the panel has not determined the level, 50% of the level that the complaining party proposed to suspend. The monetary assessment is understood as a second-best option, as it does not relieve the respondent from providing a plan to comply with the panel report (article 28.20.9 TPP). Monetary assessment is temporary and should, in principle, last a maximum of 12 months (article 28.20.10 and 28.20.11 TPP). If the defendant fails to fulfil its obligations regarding the monetary assessment, or if the monetary assessment period lapses while the defendant has not complied with the panel report, the complainant may apply countermeasures (article 28.20.12 TPP). By contrast, financial compensation has been discussed for quite some time in the WTO context (e.g. ^{Sutherland, et al., 2004}, p. 54; ^{Bronckers & van den Broek, Financial Compensation in the WTO, 2005}) and has on occasion been granted (^{O'Connor & Djordjevic, 2005}), but amendments to the DSU have failed to materialize.

In summary, the PA-AP and CPTPP offer interesting innovations vis-a-vis the DSU that strengthen the position of the complainant, e.g., regarding immediate suspension of obligations and monetary assessment. By contrast, the WTO offers multilateral surveillance of the implementation of the panel/AB report and this, as mentioned in the previous section, arguably increases legitimacy and the name-and-shame effect.

III.4.7 Summary

The three systems are available to settle state-to-state disputes that arise from the application and interpretation of the respective agreements, of a breach of an obligation, or when a member nullifies or impairs benefits, or prevents the obtention of objectives. Unlike the WTO, the PA-AP and CPTPP cover both current and planned measures, although their review is only allowed at the consultation stage. The WTO dispute settlement system applies to all covered agreements (appendix 1 DSU), while the CPTPP in particular excludes certain subject matters. In this sense, the CPTPP on the one hand extends the scope by including projected measures, but on the other hand reduces it by excluding important matters that are normally the source of most disputes at the WTO, such as trade remedies, TBT and SPS. Thus, it seems that the CPTPP is more relevant for its members in terms of its substantive concessions than for incorporating a dispute settlement system.

These three systems incorporate a first stage of consultations between parties in order to obtain an agreed settlement to the dispute, and after that a review stage by an impartial panel or arbitrator. The PA-AP opts for arbitration, whereas the DSU and the CPTPP recur to panels; however, the difference is terminological and has no substantial effect on these procedures. Procedures for selecting panelists/arbitrators vary, the CPTPP procedure being the most complex. The three systems include similar terms of reference, which the parties can modify according to the type of analysis they expect the panel/arbitrator to perform. They share procedural rights for the parties, such as presenting briefs (initial and rebuttal), at least one hearing to present oral arguments, and the protection of confidential information. They also grant third parties the possibility to participate. The three systems consider at last an initial report on which the parties can comment, and a final report.

Regarding implementation, the three systems emphasize the importance of compliance with the ruling. Defendants may be granted a reasonable period of time to comply. In cases of non-compliance, the three systems allow for compensation as a temporary solution and, as a last alternative, to resort to suspension of obligations. They include similar principles for selecting the sector where the complainant may suspend obligations. In the WTO, if the defendant objects to the proposed countermeasures, an arbitration must be followed before the complainant may start suspending obligations. Irrespective of that arbitration, the DSB must authorize WTO countermeasures. By contrast, the PA-AP and the CPTPP allow the complainant to initiate suspension without a previous authorization, but subject to review by the panel/arbitrator. The CPTPP includes monetary assessment as an alternative to retaliation.

When comparing these three systems, the most significant differences refer to the multilateral nature of WTO dispute settlement as expressed in the DSB, and to the WTO appeal stage.

Other authors have concluded that the strength of RTA dispute settlement varies according to the agreement depth, the involvement of the United States, and power asymmetry between members (^{Allee & Elsig, 2016}). Thus, we would have expected stark differences between the PA and CPTPP disputed settlement. However, while we have detected several differences, we are surprised that they are far weaker than expected.

IV.1.1 Scope of application

The scope of matters subject to dispute settlement is a central matter. We will focus on two issues: planned measures and WTO+ and WTO-extra topics. Regarding the first, the PA and the CPTPP expressly allow dispute settlement consultations regarding planned measures. These consultations are a formal stage that induces proactive regulatory cooperation when states create measures and, therefore, it decreases the probability of disputes once measures are in force. However, a PA or CPTPP panel/arbitrator shall not be established to review planned measures. By contrast, planned measures are not part of the scope of WTO dispute settlement system, arguably unless as a situation complaint under a broad interpretation of article 26 DSU. Consequently, on occasions it may be a sound procedural tactic for complainants to use the PA-AP or the CPTPP to hold consultations about planned measures; if those consultations are not satisfactory, the complainant may then turn to the WTO and submit a situation complaint.

Regarding matters where the parties to an RTA have made deeper concessions than at the WTO (WTO+) or have made concessions over matters that the WTO does not cover (WTO-extra), those RTAs obviously are the forum to settle disputes (^{Chase, Yanovich, Crawford, & Ugaz, 2016}). The PA covers few WTO-extra concessions (most notably electronic commerce and financial services), whereas the CPTPP includes several (e.g., electronic commerce, financial services, competition policy, labor, environment, etc.). Thus, there is a strong argument in favor of the PA mostly regarding WTO+ concessions, but less so concerning WTO-extra concessions. By contrast, the CPTPP includes numerous WTO-extra concessions, but excludes certain subject matters from its dispute settlement system. For instance, the CPTPP does not apply chapter 28 dispute settlement to disputes regarding antidumping and competition, perhaps to avoid conflicts of competence in matters that are treated in very similar terms at the regional and multilateral level, or because CPTPP members expected to eventually include WTO-extra matters in the WTO (^{Stoll, 2017}, pp. 15-16). Thus, we deduce that the main reason for creating the CPTPP was probably not to settle disputes, but rather to cooperatively deepen trade regulations in the context of a mega-regional agreement.

IV.1.2. Procedural stages

Regarding consultations, the PA-AP and the CPTPP include certain procedural innovations that are especially worth highlighting. First, parties may decide where and how consultations will take place. Second, these dispute settlement systems are open to holding consultations by any technological means: this decreases procedural costs, but also makes negotiations more difficult (^{Roberts & St. John, 2020}). But overall, these flexibilities could be an incentive to prefer PA or CPTPP over WTO dispute settlement if disputing parties do not expect the dispute to go beyond the consultation stage, as has been the historical trend for most WTO disputes among PA members and some WTO disputes involving CPTPP members (^{Gallardo-Salazar & Tijmes-Ihl, 2020}, pp. 653-655).

The PA includes arbitrators, unlike WTO and CPTPP panels. Some authors have argued that the reason for this is that PA members wanted to maintain the model included in bilateral agreements that they have signed with the United States (^{Álvarez Zárate & Beltrán Vargas, 2019}); we disagree, because all those bilateral agreements included a panel system. However, the difference between PA arbitrators on the one hand, and WTO and CPTPP panels on the other, is only terminological.

One of the most important concerns is how to prevent parties from blocking the appointment of panelists or arbitrators (^{Lester & Manak, The Fundamental Flaw in the New NAFTA Deal, 2018}). WTO rules have shown to be robust in this regard (in contrast to rules on selecting AB members). At least in theory, PA-AP and CPTPP rules seem quite robust too (in the same vein, Lester, Manak, & Arpas, Access to Trade Justice: Fixing NAFTA's Flawed State-to-State Dispute Settlement Process, 2019, pp. 70-72). It will be interesting to observe how much effort PA and CPTPP parties will invest in preparing lists of arbitrators or panelists, as it will reflect how much importance they ascribe to these dispute settlement systems and their future operation.

Even though WTO appeals are factually not available, they remain a right for the parties to the dispute. Thus, in cases where a party is not planning to comply with an adverse panel report, it may suspend the procedure indefinitely simply by appealing “into the void”. Thus, the complainant is left with a panel report that the DSB cannot adopt and that the defending party cannot be forced to comply with. In this context, defending parties can be forced to comply with PA-AP and CPTPP reports, and that is an incentive for complaining parties to resort to these regional fora instead of bringing their dispute to the WTO, especially when the complainant expects that the dispute would reach the WTO AB (^{Gallardo-Salazar & Tijmes-Ihl, 2020}, pp. 655-656).

According to WTO dispute settlement patterns of PA and CPTPP members, the effects of the AB crisis vary for different parties. The five WTO disputes among PA members did not even finish the WTO panel stage and were settled by consultations or withdrawn. Consequently, if PA members expect to settle their future disputes following this pattern, the WTO AB crisis will arguably not influence the PA members’ choice of forum, as both the WTO and the PA offer a forum for dispute settlement through diplomatic means. By contrast, WTO dispute settlement patterns among CPTPP show a different picture. WTO disputes among certain CPTPP members have gone beyond the panel stage. For those CPTPP members, the AB crisis will arguably affect their choice of forum, as claimants will probably prefer the CPTPP over the WTO. However, the reduced scope of matters subject to CPTPP dispute settlement (in comparison to the WTO) means that members will not be able to effectively settle disputes regarding a number of matters either at the WTO or at the CPTPP (^{Gallardo-Salazar & Tijmes-Ihl, 2020}, pp. 653-656).

IV.1.3.Compliance

Another important aspect is compliance. The DSU and the CPTPP include the possibility to grant the defendant a reasonable period of time to comply. By contrast, the PA-AP does not, making the dispute settlement process more expeditious, at least in theory.

Although there was some debate as to whether WTO rules allowed efficient breach (^{Bello, 1996}; ^{Jackson, 1997}), by now the question seems settled that WTO members have a duty to comply with DSB decisions. Meanwhile, articles 17.20.1 and 17.20.4 PA-AP and 28.20.15 TPP univocally articulate a duty to comply with arbitrator/panel rulings. The effectiveness of suspending obligations to induce compliance has been discussed at large in the WTO context (^{Tijmes-Ihl, Jurisprudential developments on the purpose of WTO suspension of obligations, 2014}, pp. 32-35), because it could go unnoticed against a respondent with a large market, or even be counterproductive for the claimant since it increases the import price in the domestic market regarding sectors that may not be related to the original dispute (^{Bronckers & Baetens, Reconsidering Financial Remedies in WTO Dispute Settlement, 2013}, p. 282). To tackle these problems, the CPTPP allows the respondent to temporarily pay a monetary assessment to prevent the complainant from suspending obligations as a second-best option to restoring the balance of concessions through compliance (article 28.20.15 TPP stresses that it does not replace full implementation of the panel report). Monetary assessment is arguably an attractive alternative, as it provides a provisional remedy that does not, at least indirectly, affect the complainant’s interests or constitute only a symbolic victory. In addition, monetary assessment may be appealing for respondents that are unable to comply immediately with a panel ruling due, for instance, to political concerns or internal market pressures. However, it is not clear how it will be calculated (^{World Trade Organization, 2013}, pp. 37, 50-51), and the consequences of its application are uncertain, especially considering the heterogeneity among member states in terms of economic development and power. By contrast, financial compensation is “generally considered not to be available in the WTO”, although “there have been disputes in the WTO that reportedly resulted in arrangements involving financial transfers between the parties,” namely US - Section 110(5) Copyright Act and US - Upland Cotton (^{World Trade Organization, 2013}, p. 6 and footnote 9).

In summary, we conclude that at the procedural level both RTAs represent a viable alternative to WTO dispute settlement, especially in the current AB crisis.

IV.2.1 Institutional structure

To begin with, we may ask if the WTO institutional structure related to dispute settlement, mostly the Secretariat, the DSB and the standing AB, may be a reason to prefer WTO over PA-AP and CPTPP dispute settlement. The main advantages of having a Secretariat relate to the fact that it “exerts enormous influence on the culture of an agreement” (^{Toohey, 2017}, pp. 101-102), while the DSB institutionalizes multilateral oversight over disputes. By contrast, the main benefits of not having these organs involve faster and less bureaucratic processes (^{Hillman, Dispute Settlement Mechanism, 2016}, p. 102). Also important are fewer administrative and infrastructure costs for disputing parties (^{Toohey, 2017}, pp. 101-102). This last advantage is especially significant if members to the agreement anticipate that disputes will be infrequent, or if dispute settlement is probably not the main purpose of an RTA, as is the case regarding the AP and the CPTPP (^{Gallardo-Salazar & Tijmes-Ihl, 2020}). In addition, lighter institutional structures may reflect a conscious decision for dispute settlement to reflect the power dynamics between disputing parties (particularly in case of non-compliance), and to keep disputes at a bilateral level without the intervention of other members. Thus, it is most likely that PA and CPTPP members did not intend to replicate the WTO dispute settlement institutions, but instead wanted to create an efficient regional system to deal with mainly bilateral conflicts.

In other words, were it not for the AB crisis, multilateral dispute settlement at the WTO would arguably be a better option regarding disputes that transcend the merely bilateral level. For instance, a measure that may affect states that are not members of the RTA, a dispute that may have strong political elements or where the complainant may want to create a multilateral precedent for future disputes, etc. (^{Davis, 2006}; ^{Busch M. , 2007}). However, in most cases the current AB crisis will offset these multilateral advantages. By contrast, PA and CPTPP parties that are also parties to the WTO interim appeal arbitration arrangement mentioned before (namely Australia, Canada, Chile, Colombia, Mexico, New Zealand, Singapore, and Peru) may perhaps find WTO dispute settlement more attractive than the PA and CPTPP.

IV.2.2 Special and differential treatment

WTO dispute settlement includes rules on special and differential treatment (S&DT) for developing countries, whereas the PA-AP and CPTPP do not. Will this omission be significant enough for developing countries to prefer the WTO dispute settlement system? Perhaps not, as some authors have underscored that the WTO dispute settlement has been unable to offset the disadvantages that developing countries face, especially considering that many disputes are protracted and expensive (^{Walters, 2011}). Be that as it may, it would be an interesting question for future research why the PA and the CPTPP do not include S&DT.

IV.2.3. Transparency

Openness and participation are also important issues. The three systems ensure confidentiality during consultations (articles 4.6 DSU, 17.5.8 PA-AP and 28.5.8 TPP). Regarding the litigation stage, some people have argued that the WTO dispute settlement system has an insufficient degree of openness towards the public (^{Charnovitz, 2004}; ^{Feeney, 2002}), especially apropos hearings and amicus curiae briefs. WTO panel deliberations and AB proceedings are confidential (articles 14.1 and 17.10 DSU). Apart from that, there is no general rule on openness or secrecy of hearings and it has been up to the parties to WTO disputes, the panels and the AB to decide on a case-by-case basis. By contrast, the PA-AP and the CPTPP require at least one public hearing, although protecting confidential information. CPTPP procedural rules require panels to consider -under certain circumstances- requests to submit amicus curiae briefs (article 28.13(e) TPP); by contrast, the DSU and the PA-AP do not refer to this issue. Nevertheless, arguably only under exceptional circumstances would these rules regarding openness and amicus curiae briefs be a deciding factor when the complainant chooses forum, perhaps if the subject matter has a very high social impact or if the complainant wants to use openness and participation as a tactical tool against the defendant.

In summary, it seems plausible that complainants would often prefer WTO dispute settlement because of its stronger institutions, its multilateral nature and S&DT, whereas relatively low levels of openness and participation would most probably seldom counterbalance those strengths. In other words, under normal circumstances, it is likely that institutional incentives would have been strongly favorable for WTO dispute settlement over the PA-AP and CPTPP. In addition, we have to consider the peer effect of other members recurring to WTO dispute settlement, and the practical litigation experience already gained at the WTO, in contrast to the still untested PA and CPTPP dispute settlement systems. Yet again, the current AB crisis evidently offsets these institutional strengths.

IV.2.4. Summary

Are the PA-AP and CPTPP alternatives to WTO dispute settlement? From a procedural perspective, the scope of application of the PA-AP and CPTPP include consultations on planned measures, and they also include WTO+ and WTO extra matters (though the application of the CPTPP dispute settlement system is to some degree restricted). The PA-AP and the CPTPP offer complainants a definitive and binding solution - something that the WTO, under current circumstances, is not able to ensure. Avoiding a non-operational AB is especially important for CPTPP members, as a large part of WTO disputes between CPTPP members have reached the appeal stage (^{Gallardo-Salazar & Tijmes-Ihl, 2020}, pp. 645-652). PA-AP and CPTPP procedures ensure representativeness as each disputing party appoints one panelist/arbitrator, they limit the possibilities of blocking appointments, and they guarantee the independence of the panel/arbitrator president. At the level of compliance, the CPTPP provides monetary assessments. Finally, both RTAs provide disputing parties with flexibility regarding logistical aspects, such as the place and technological means.

From an institutional perspective, the WTO dispute settlement system has its own strengths, such as the rules regarding S&DT. However, these features are arguably not very relevant for PA and CPTPP members, as WTO disputes among CPTPP parties have usually been among members with similar economic development levels (obviously, this also applies to the PA members). Another asset of WTO dispute settlement is the involvement of the DSB and the Secretariat. The PA-AP and the CPTPP guarantee public access to hearings and the CPTPP includes the obligation to consider amicus curiae briefs. These aspects are relevant especially in the context of disputes that involve socially contested issues.

Thus, PA and CPTPP members will likely recur to the WTO regarding disputes where rules on S&DT are important, that require the institutional support of the DSB or the Secretariat, or when the complainant wants to multilateralize the dispute or create a multilateral precedent.