By Sarthak Malhotra
Amidst the widespread recognition of custom as a source of International Law, there have always been echoes of those who deny that custom is signficant as a source of law.While the importance of custom cannot be denied, it will also not be an exaggeration to say that the value of custom has decreased because of widespread codification of International Law.
Does this mean that Customary International Law is obsolete now ?
Professor Trachtman‘s reply is in affirmative.
In his latest scholarship, Professor Trachtman, analyses 300 rules of CIL, only 13 of which are found to be not codified. He argues that CIL has played an important role in regulating and protecting human rights but the focus should now be shifted on more effective mechanisms(such as treaty-based hard law and soft law).
According to Mr. Trachtman, CIL has several important limitations.
CIL cannot be made in a coordinated manner in advance of events, it cannot be made with sufficient detail, it cannot be made with sufficiently heterogeneous reciprocity between states,it cannot be made with specifically-designed organizational support, it is generally not subject to national parliamentary control, it purports to bind states that did not consent but failed to object to its formation, and it provides excessive space for auto-interpretation by states, or for sometimes insufficiently disciplined interpretation by judges.
He argues that,
In the CIL setting, it may be that the benefits of simultaneity are lost, but states might still anticipate the unraveling of cooperation, and veer away from defection. The problem is that the first state is unlikely to adopt a compliant practice, because it will recognize that the dominant behavior of other states, after observing the initial compliant practice, is to free ride.
Trachtman’s analysis involves arbitrarily selected, but highly regarded group of secondary sources. He, then, examined the general extent to which rules identified were incorporated in treaty law, or codified by International Law Commission. This research reveals that only 13 (4.33%) of the 300 identified rules have not been codified or incorporated in treaties. It is quite surprising that even after removing the ILC codifications, only 43 (14.33%) of the aggregate of all CIL rules have not been codified yet.
While I have always supported the importance of Customary International Law because it is more precise in some areas of international law, e.g. International Humanitarian Law, Trachtman’s stellar research is certainly thought provoking and will force many others to rethink. Though subject to many caveats, Trachtman’s latest research is a recommended reading for for all international law enthusiasts.
You can read his article here. Do not forget to skim through the appendix to the article.
 W. Friedman, The Changing Structure of International Law, New York, 2964, pp. 121-3
Jane Black, Maurice D. Levi & David de Meza, Creating a Good Atmosphere: Minimum Participation for Tackling the ‘Greenhouse Effect,’ 60 ECONOMICA 281 (1993)