I don't think that "international law" as referred to in this discussion was intended to mean "law binding states in regards to bilateral and multilateral relationships between themselves (states), emanating from bilateral and multilateral agreements between themselves (states),"  Rather, I expect that what was meant was "principles of international law," as referred to in ICANN's Articles of Incorporation, Article 4, (emphasis added):

The basic notion is that a general principle of international law is some proposition of law so fundamental that it will be found in virtually every legal system. When treaties and customary international law fail to offer a needed international rule, a search may be launched in comparative law to discover if national legal systems use a common legal principle. If such a common legal principle is found, then it is presumed that a comparable principle should be attributed to fill the gap in international law. (Janis, An Introduction to International Law)

There is a useful discussion of the interpretation of the term "principles of international law" in the Declaration of the Independent Review Panel in ICM v. ICANN, which summarizes the arguments of both parties' international law experts before the panel comes to its own conclusion:

138. In the view of ICM Registry, principles of international law are

applicable; that straightforwardly follows from their specification in the

foregoing phrase of Article 4 of the Articles, and from the reasons given in

introducing that specification. (Supra, paragraphs 53-54.) Principles of

international law in ICM’s analysis include the general principles of law

recognized as a source of international law in Article 38 of the Statute of the

International Court of Justice. Those principles are not confined, as ICANN

argues, to the few principles that may be relevant to the interests of Internet

stakeholders, such as principles relating to trademark law and freedom of

expression. Rather they include international legal principles of general

applicability, such as the fundamental principle of good faith and allied

principles such as estoppel and abuse of right. ICM’s expert, Professor

Goldsmith, observes that there is ample precedent in international contracts

and in the holdings of international tribunals for the proposition that nonsovereigns

may choose to apply principles of international law to the

determination of their rights and to the disposition of their disputes.


139. ICANN and its expert, Professor David Caron, maintain that

international law essentially governs relations among sovereign States; and

that to the extent that such principles are “relevant” in this case, it is those

few principles that are applicable to a private non-profit corporation that

bear on the activities of ICANN described in Article 3 of its Articles of

Incorporation (supra, paragraph 2). General principles of law, such as that of

good faith, are not imported by Article 4 of ICANN’s Articles of Incorporation;

still less are principles derived from treaties that protect legitimate

expectations. Nor is Article 4 of the Articles a choice-of-law provision; in

fact, no governing law has been specified by the disputing parties in this

case. If ICANN, by reason of its functions, is to be treated as analogous to

public international organizations established by treaty (which it clearly is

not), then a relevant principle to be extracted and applied from the

jurisprudence of their administrative tribunals is that of deference to the

discretionary authority of executive organs and of bodies whose decisions

are subject to review.

140. In the view of the Panel, ICANN, in carrying out its activities “in

conformity with the relevant principles of international law,” is charged with

acting consistently with relevant principles of international law, including

the general principles of law recognized as a source of international law. 64

That follows from the terms of Article 4 of its Articles of Incorporation and

from the intentions that animated their inclusion in the Articles, an intention

that the Panel understands to have been to subject ICANN to relevant

international legal principles because of its governance of an intrinsically

international resource of immense importance to global communications and

economies. Those intentions might not be realized were Article 4

interpreted to exclude the applicability of general principles of law.

While not dispositive, the Declaration can hardly be dismissed as inconsequential.  It is clearly from even a brief review of the document that it is the result of many of hours of careful research, analysis and argument by knowledgeable professionals on both sides of the case, as well as a careful review by the panel (which included a former presiding judge of the ICJ, a distinguished scholar of international arbitration and a former US District Court judge).  Given that these contributors trod the very ground upon which we now walk, the Declaration is, at the least, instructive.