[Julian Davis Mortenson is Assistant Professor of Law at Michigan Law.]
I am most grateful for the thoughtful comments offered by Bart, Richard, and Ulf. Their observations are well-informed, generous, and extremely useful in advancing the conversation about treaty interpretation. So first and foremost, sincerest thanks to each of them.
In my response, I hope (1) to clarify the question that seems principally at issue in the discussion so far, and (2) to suggest how the historical evidence helps answer that question. As Ulf rightly points out, the article’s aim is not to march through a unified field theory of treaty interpretation in the exhaustive fashion of a single subject treatise. It is, rather, to debunk a theoretically central misunderstanding about the interpretive role of travaux under the VCLT as a historical document.
The article is thus fundamentally a historical inquiry. But it also has obvious doctrinal implications. While those implications are not the article’s central concern, I will briefly expand their logic as outlined on page 5 of the draft posted on SSRN. I take some time to spell this out because—with the exception of Richard’s kind and detailed approbation of the historical analysis—the commentaries in this symposium understandably engage less with the particulars of the history than with its doctrinal implications for contemporary interpretive practice.
So here is a sketch of the case for those implications:
- First: Every mainstream understanding of treaty interpretation contemplates the use of travaux to resolve ambiguity that remains after the methods described in Article 31 are applied. We argue about the use of travaux in other circumstances. But no one seriously contests that they are not just available but potentially decisive in the face of ambiguity. (This is why any perceived doctrinal circularity is illusory. Since all parties to the debate are in agreement on at least this point, for doctrinal and argumentative purposes we can treat the relevance of drafting history in cases of ambiguity as an axiom requiring no proof.)
- Second: The complex, multilayered, and rather-quirkily-drafted provisions of Article 31 and 32 are a textbook example of such ambiguity, both in their individual meanings at the subsection level and in their overall structural interrelationship. One might reasonably rely (for example) on the structural separation of Articles 31 and 32 to conclude that they instantiate an interpretive hierarchy that disfavors travaux. But one might also reasonably rely (for example) on the existence of the “special meaning” and “confirm[ation]” provisions to conclude that they do not. This ambiguity is stubborn, and no amount of deductive gymnastics can make it disappear.
- Third: Because the treatment of travaux under Articles 31 and 32 is ambiguous, every mainstream theory of treaty interpretation must concede a potentially decisive role for the VCLT’s drafting history in resolving that ambiguity. Putting it as one might in a legal brief: assuming arguendo with the most conservative commentators that resort to travaux is available only in the case of ambiguity, that condition is easily satisfied here.
- Fourth: Careful review of the VCLT travaux—and it is on this point that the article focuses—demonstrates that Articles 31 and 32 were understood to reject a hierarchical or mechanistic view of interpretation. The holistic view of interpretation adopted by the drafters extended in particular to the use of travaux, which were viewed as automatically incorporated among and conceptually equivalent to the many other (potentially contradictory) indicators of legal meaning enumerated in the VCLT.
With the exception of the last bullet point, these statements are obviously asserted rather than demonstrated. But if each of them holds up, then as a matter of modern legal meaning the VCLT instantiates neither an interpretive hierarchy generally nor a hostility (suspicion, inhospitality, etc.) toward drafting history specifically. The Vienna settlement erected neither barriers, nor thresholds, nor negative presumptions regarding the use of travaux. Instead, it incorporated drafting history as a central and indeed crucial tool for identifying correct legal meaning.
Bart puts his finger right on the most important open question about this bottom line doctrinal conclusion. Given the conceded prevalence of learned professions that such a hierarchy does exist, it’s not out of bounds to argue that subsequent practice under the VCLT conflicts with its original meaning. (Note that, as explored in a shorter paper available here, the VCLT does not tell us how to resolve such a conflict. But bracket that for now.)
Partly because of the stark contradiction that Ulf observes between actual interpretive practice and professions of interpretive principle, however, it is my strong instinct that no such practice has in fact arisen among states parties to the VCLT. But the burden here will be on anyone seeking to dislodge the Vienna settlement. They will have to show, in the precise terms of Article 31, that contrary “subsequent practice in the application of the treaty . . . establishes the agreement of the parties regarding its interpretation.” If you can’t make that showing, then it’s hard to avoid the following doctrinal conclusion: Drafting history is generally and automatically available as a source of meaning in every single case. And that’s true even if—as Richard so nicely shows with the meaning of “poison” under the Rome Statute—the particular travaux of a particular treaty might not in fact illuminate a particular question facing a particular interpreter at any particular moment.