The U.S. veto was based not on Chang’s lack of qualification, but on his decisions. This sets a highly dangerous precedent, which the U.S. may come to regret. In the future, any WTO member can follow the U.S. example and veto the reappointment of judges it considers inappropriate.
.. As the consensus principle applies in the organization, in effect giving every member state a veto, such behavior could, in a worst-case scenario, completely stall the dispute settlement system. Why is the U.S. taking such a risk by rocking the system?
.. One simple reason is that most of the disputes that the U.S. has been engaged in have concerned the EU and China — highly important trading partners that are not yet covered by bilateral trade agreements. China, the EU and the U.S. appear most frequently as parties to disputes at the WTO, indicating how heavily the largest economies in the world rely on the dispute settlement system.
.. Could it have been intended as an attempt to make such reappointments a political exercise, similar to the appointment of judges to the U.S. Supreme Court? If so, the U.S. has totally misjudged the difficulty of managing multilateral relations to reach political consensus. This seems unlikely.