Is there such a thing as obiter dictum in the WTO DSM?

Yesterday's General Council meeting was quite entertaining, to say the least, with "hatchets", "rabbits" & "dogs" flying in the air when the US and China engaged in several rounds of heated exchange. While China blamed the US for wrecking "the crown jewel of the WTO", the US repeated its attack on the Appellate Body by saying:

"Despite years of warnings from my predecessors, and expressions of concern from respected WTO voices, including former Directors-General, the Appellate Body not only has rewritten our agreements to impose new substantive rules we Members never negotiated or agreed, but has also been ignoring or rewriting the rules
governing the dispute settlement system, expanding its own capacity to write and impose new rules."

As the US stated when it blocked the reappointment of Prof. Seung Wha Chang two years ago, its main problem with the alleged "unapproved rule-breaking and rule-making" by the AB is reflected in 4 cases, i.e, DS 437, DS 449, DS 453, & DS 430. In three of these cases, Prof. Chang was accused of giving out "obiter dicta", something that he was not supposed to do. But could there really be something called "obiter dicta" in the WTO dispute settlement system?

In a paper just published in the World Trade Review, I reviewed the issue with a detailed examination of each of the three possible underlying premises of the US argument, i.e.,

1, the WTO legal system based on Common Law;

2, WTO follows stare decisis; or

3, the WTO has rules against dicta.

Unfortunately. none of these premises can stand. Thus, the US allegation is nothing but "dictum on dicta"!