In my view, this separate opinion provides a measured, but firm, rebuttal to the criticism levelled against the Appellate Body during the recent reappointment controversy. Specifically, the separate opinion rebuts the US view that the AB should not address any issues raised in an appeal where it is not strictly necessary to dispose of the case. The separate opinion starts out by emphasising that the AB has not only the authority, but even a “legal ‘duty’” to address each of the issues raised by the parties to an appeal. On this view, the default position is that the AB must address each and every legal issue raised by the parties. The separate opinion then qualifies this somewhat by conceding that “addressing an issue” does not necessarily mean that the AB has to make “specific findings” on the claim in question; instead, it can confine itself to explaining why it did not need to resolve the issue. However, the separate opinion then immediately qualifies the qualification by noting that whether “addressing” the issue in this way is appropriate is “for the Appellate Body to decide in light of the particular circumstances of each case”. Importantly, these “circumstances” are not limited to the question of whether the AB could dispose of the case without ruling on the issue, but also include “the nature of, and relationship between, the relevant claims on appeal, as well as their implications for implementation”. What does this mean? By “nature of the claims”, the separate opinion could be referring to claims that have no implications for the consistency of the measure at issue with WTO law, for example, where a party appeals the legal interpretation developed by a panel without asking for a reversal of the panel’s legal conclusions (the US itself has made such claims on appeal). If the AB had to confine its analysis to claims that have to be addressed to resolve the dispute, the AB could never make any findings on such “pure interpretation” claims – a clear abdication of its judicial function. By the “relationship between claims”, the separate opinion could be referring to situations where two claims concern essentially the same issue (e.g., parallel discrimination claims brought under different agreements) as opposed to claims that concern cumulative elements of a single test. With regard to the latter, the references to “implications for implementation” and to the DSU’s objective to achieve a “positive solution to a dispute” are particularly telling. Even if the AB could dispose of a case by ruling on a single element of a test (for example, by declaring a panel finding moot on the basis that the panel erred in its assessment of likeness in a situation in which the AB is unable to complete the analysis on likeness), it could make sense for the AB to go on to examine the other elements of the panel’s analysis (e.g., on LFT and exceptions) if it expects that the issue will be relitigated in some form at a later point (either in a new dispute or a 21.5 proceeding). As I read it, the separate opinion’s bottom line is this: the DSU accords the AB considerable discretion (“a matter for the Appellate Body to decide”) to “address” the claims before it as it sees fit. As we learned earlier this year, that is not the US’s view. Later on, the separate opinion goes even further, asserting that the AB “is not required to provide reasons as to why it adjudicates a particular issue properly raised by the parties on appeal in accordance with Article 17.6 of the DSU”. Essentially, the separate opinion is saying that the AB does not owe anyone an explanation of why it decides to make a finding on a legal issue that is properly before it. Such an explanation is only owed, the separate opinion suggests, where the AB decides not to make findings on an issue. This is directly contrary to what the US has been arguing in the reappointments controversy. Finally, the separate opinion suggests that, in deciding whether to offer “interpretative guidance”, the AB has to take into account the “systemic interest” of WTO Members, including the third parties to a dispute, “in receiving an Appellate Body report that properly clarifies the existing provisions of the covered agreements”. This can be read as a direct rebuttal to the US’s claim that the AB “is not an academic body that may pursue issues simply because they … may be [of interest] to certain Members in the abstract”. Arguably, one of the principal reasons why third parties participate in AB proceedings is that the interpretative issues raised by the appeal are of interest to them “in the abstract”. By explicitly acknowledging the interest of third parties and the WTO membership at large, the separate opinion asserts that the AB should take this “abstract” or “systemic” interest – as the opinion calls it – into account.