Here is an interesting exchange from last week's hearing in the USMCA San Martín mine labor dispute about the role of WTO case law in interpreting the USMCA provisions at issue:
Panelist: Mexico raised the question that the United States has not provided any legal authorities for its positions. Would the United States like to respond to that?
U.S.: In this case, the legal arguments that we're making relate to the interpretation of the USMCA and the provisions of the rapid response mechanism. To interpret those, the panel should look at the text, in context, in light of the object and purpose. There aren't cases on these issues and looking to the text is what we've relied on for purposes of supporting interpretations. So we didn't provide legal treatises or articles, if that's what they're referring to, because we didn't think it was necessary to do so.
Panelist: What weight should we give then to the jurisprudence that's been provided by Mexico IMMSA [Industrial Minera de México, S.A.], if any?
U.S.: Under the Vienna Convention, where the meaning of a treaty isn't clear from the text and context, the panel can look to distinguished jurists, I think is how they are referred to. So the opinions in other adjudicatory bodies, to the extent that they speak to issues that might be relevant to the proceedings, if the panel finds them useful or persuasive, the panel can look to those sources. They certainly aren't binding on the panel.
And in this case, because these provisions are unique, the WTO cases, for example, that IMMSA refers to are not persuasive. In fact, IMMSA gives in its brief many examples of potential like products that it suggests would not be considered like that, in my experience at the WTO, absolutely would be considered like. ... they don't speak directly to these issues. I don't think the panel needs to evaluate those in order to make its determination on what things would be in competition. ... They aren't binding on the panel. ...
When we are talking about the role of past cases as precedent, I feel like we are often talking about the degree of persuasiveness. That degree may vary depending on factors such as which adjudication body is the source of the prior case, or whether it's from a higher court or the same level court. It's difficult to come up with language that captures the nuances of persuasiveness though. It's easy to say "no binding precedent," but defining persuasiveness is a challenge.
