The recent death of Allan Farnsworth, the architect of the (Second) Restatement of Contracts, has spurred a retrospective evaluation of the value of the Restatement Project. In this vein, I think it would be valuable to extend this re-evaluation to the role of the International Law Commission and its ongoing projects involving the codification of customary international law.
Under the ILC's founding resolution the ILC was empowered to both "codify" current practices found in customary international law as well as aspects found in the "progressive development" of international law. In theory, the dichotomy of codification and progressive development is supposed to be encapsulated in the creation of conventions of "draft conventions." In reality, the ILC has been unable to straddle these two responsibilities and has stuffed substantial additions of progressive development into its codification efforts. As such, the ILC can claim that its conventions and commentaries do not suffer the problem Randy Barnett specifies of being limited to a frozen snapshot of the development of law. However, an inverse complaint is appropriately leveled at the Commission's work. Specifically, the ILC consistently attempts to bootstrap immature notions of what could become CIL directly into its codification.
I understand that the members of the ILC and legal academia generally have a proclivity to build beyond the limits of a building's foundation, but just as young academics should know "the classics" before playing with the bells and whistles of law, international law needs to expand and strengthen its foundation before wishing new law upon a system unequipped to handle it. The taint of notions clearly not present within CIL taints the entire codification process. One of the reasons that the Restatement project could flourish is the enormous number of samples of common law upon which its authors could draw. International law does not yet have the depth nor consensus to build an exhaustive codification of laws which have not been sufficiently mined and explored. In this sense, it seems to me that international law would benefit from a true codification of customary international law that could be drawn upon with less controversy and more consensus.