That international organizations are established and run by States may provide a reason to resist assimilation with States as regards certain rules of general international law, particularly in the field of treaties and responsibility. It is one thing to say that States and international organizations are comparable so that rules of general international law that bind States individually also bind their organizations on the international plane, and quite another to suggest that by acting collectively States can circumvent their individual obligations, ignore treaty commitments assumed by the corporate entities that they set up, and shield themselves from any individual liability resulting from collective wrongful conduct. Yet, in the debates at the International Law Commission, that persuasive objection to an analogy between States was discarded in light of emerging international practice and opinio juris. The chapter considers how the Commission extended to international organizations the pacta tertii rule and the principle of independent responsibility that apply to ‘unitary entities’. It also discusses provisions which, seeking to prevent circumvention of international obligations, have been proposed to mitigate an analogy taken too far.