That’s the provocative conclusion of the latest research by Joel Trachtman. Trachtman’s articles are typically succinct and seductive, so you owe it to yourself to read the short article (and skim the long appendix).
Trachtman examined 300 different CIL rules and found that only 13 (4.33%) have not been either incorporated in treaties or codified. Trachtman argues that the move toward treaties is because CIL cannot respond effectively to the great modern challenges of international society: global environmental protection, international public health, cybersecurity, financial cataclysm, and liberalization of movement of goods, services, and people. Trachtman also argues that CIL is incapable of addressing enduring challenges of regulating war, protecting human rights, and reducing poverty.
According to Trachtman, the reasons for CIL’s obsolescence are manifold. CIL (1) cannot be made in a coordinated manner; (2) cannot be made with sufficient detail; (3) cannot be made with sufficiently heterogeneous reciprocity; (4) cannot be made with specifically-designed organization support; (5) is not subject to national parliamentary control; (6) purports to bind states that did not consent but failed to object to its formation, and (7) provides excessive space for auto-interpretation by states or undisciplined judges.
For Trachtman, the obsolescence of CIL should lead states to stop arguing about CIL and start legislating mutually beneficial transactions. It should also lead NGOs and advocates to stop trying to “bootstrap a desired CIL past a target state” and instead engage with those states in treatymaking. Academics should “focus our analysis on the politically immanent, interdisciplinary, work of developing proposed rules that are administratively workable and effective, and that achieve actual social goals.” He suggests that the international legal system could survive just fine without CIL. So stop worrying about custom and learn to love treaties.
This is powerful stuff. With this piece Trachtman has done a great service to the academic debate on the relevance of CIL. Perhaps unwittingly, he also has done great service to customary international law by offering a comprehensive appendix that lists 300 of the most important CIL rules. If you want students to quickly grasp the scope and contours of CIL, just peruse the appendix.
Applying Trachtman’s thesis to my world of international economic law, I must concur with much of Trachtman’s argument. International trade law, in particular, is all about negotiating, interpretation, and enforcing treaties. We rarely if ever discuss CIL in a trade class. The very nature of an FTA is that it confers rights and obligations exclusively its Members. The defects of CIL are significant enough that trade law is almost exclusively treaty law.
International arbitration is more complicated. Trachtman only identifies two CIL rules for international economic law (Rule 207 and 208), both codified in the investment chapter of NAFTA Chapter 11. But the norm for investment arbitration is to articulate a general standard of protection in bilateral investment treaties (or FTA investment chapters), and then leave it to arbitral tribunals the task of devising detailed obligations from those general standards. Indeed, most BITs require States to afford investors protection consistent with international law, leaving to tribunals the task of discerning precisely what international law requires. BITs are not codifying CIL, but in a sense they instruct tribunals to create it.
Trachtman would not disagree that CIL is still relevant in limited contexts. He specifically recognizes that occasionally CIL is more precise than a codified rule. International humanitarian law and investment arbitration may be such categories. Likewise, Trachtman would concede that CIL is relevant where the treaty is binding on only a few states, as is the case with rules of state succession.
One can easily find selective instances where Trachtman is wrong. But what I doubt critics will be able to do is refute his general thesis that the codification of international rules through treaties has made CIL increasingly obsolete.