A couple weeks ago, I asked this question:
What steps will the U.S. take now to prove its compliance [in Tuna]? Note that Mexico has already proposed suspension of concessions, and the U.S. has objected to the level of suspension, so the matter has been referred to arbitration. Is the U.S. hoping the arbitrator will look into whether compliance has been achieved? Or will it request another Article 21.5 panel to examine this issue?
On 11 April, the United States submitted a request for a compliance panel under Article 21.5 of the Dispute Settlement Understanding (DSU) to examine measures adopted by the US in March 2016 with a view to bringing itself into conformity with the recommendations and rulings in “US – Tuna II (Mexico)”, DS381.
The compliance panel will determine whether these measures are consistent with the WTO agreements and if they bring the United States into compliance with its obligations under the Technical Barriers to Trade Agreement and the General Agreement on Tariffs and Trade (GATT) 1994. This follows a request filed by Mexico on 10 March 2016 seeking authorization from the Dispute Settlement Body to suspend tariff concessions and other obligations in the goods sector for an amount of USD 472.3 million annually. After the United States objected to the level of suspension of concessions proposed by Mexico, Mexico's request was referred to arbitration under Article 22.6 of the DSU.
I'm assuming it will be the same people serving on the 21.5 compliance panel and the 22.6 arbitration panel. How will they coordinate these processes in terms of timing?