Article 12 of the DSU specifies these time-frames for panels to issue reports:
8. In order to make the procedures more efficient, the period in which the panel shall conduct its examination, from the date that the composition and terms of reference of the panel have been agreed upon until the date the final report is issued to the parties to the dispute, shall, as a general rule, not exceed six months. In cases of urgency, including those relating to perishable goods, the panel shall aim to issue its report to the parties to the dispute within three months.
9. When the panel considers that it cannot issue its report within six months, or within three months in cases of urgency, it shall inform the DSB in writing of the reasons for the delay together with an estimate of the period within which it will issue its report. In no case should the period from the establishment of the panel to the circulation of the report to the Members
exceed nine months.
In practice, however, panels take much longer. And as the United States keeps pointing out, the Appellate Body has been taking longer than 90 days (and doing so without the consent of the Members).
With this in mind, I was struck by something former USTR Susan Schwab said at the annual Georgetown Law International Trade Update last week (I wasn't there, so I don't have the full context for the quote):
One potential remedy for the WTO’s dispute settlement system would be to hasten the process so a complaining member can see an issue resolved, receive compensation, or be authorized to retaliate sooner, Schwab said.
Is it possible that speeding up WTO disputes could be a way to achieve a set of reforms that satisfy the U.S. concerns about the Appellate Body? At the panel stage, for example, you could shorten the process by having only one panel meeting, or getting rid of the interim review, or by putting limits on the length of submissions. That would probably give you a shorter report, with fewer issues to appeal (although perhaps the reduced clarity would lead to more appealed issues?). And then at the appellate stage, you could narrow the scope for appeals by setting a higher standard for DSU Article 11-type appeals; clarifying that examination of measures is a factual question; and restoring the 90 day period for circulating Appellate Body reports (page limits on submission length would help here as well). Perhaps by packaging all of this together, the chances for negotiating an end to the impasse in Appellate Body appointments would be increased.