Professor Weisburd's reply to my essay adds helpful insights to the fascinating issue of the impact of treaties upon customary international law. For the most part, I think the positions on both sides have been clearly drawn, leaving to the reader the ultimate judgment on the merits.
One instance where the position is not so clearly drawn, however, is the question of what custom-creating force we can find in a treaty that itself disavows its custom-creating force. If the language says that the treaty is a matter of comity only, Professor Weisburd argues that the treaty cannot give rise to a customary rule of law. My position to the contrary is that the parties cannot in this way carve out for themselves an exception to the general metarule that treaties generate custom, any more than they could effectively use treaty language to confine the treaty rule to themselves by saying, in the treaty, that their particular treaty shall have no general customary law-creating force for nonparties. In neither case do the parties have a general legislative competence that extends to nonparties.
A Brief Rejoinder,
21 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vjtl/vol21/iss3/4