 One prominent approach traces the legitimacy of international law to the actual consent (explicit or implicit) of its subjects. States are bound by treaties insofar as they consent to them; meanwhile, states are bound by customary international law insofar as they have explicitly (opinio juris) consented to its norms in the process of their formation, or else implicitly done so (e.g., by failing persistently to object to them). One problem with the consent theory is that international law includes norms that purport to bind states independently of whether they consented to them, such as norms that came into being before the state came into existence, or norms that have achieved the status of jus cogens norms (Dworkin 2013). In response, the steadfast defender of the consent view might reply, “So much the worse for the legitimacy of these norms”.